audiopollution or others could chime in, my current feeling is that if you do the multi-bay thing with FW800 then raid is an interesting option.
something to read up and geek out on, this whole RAID thing
if i am not mistaken, the key is the RAID controller, which is either software based (disk utility in mac os X) or hardware based (more expensive expansion bay set ups).
again, just throwing an idea out there, lets say a FW800 expansion bay thingy, throw two or three 7200rpm 8mb cache 3.5" 100+Gb drives in there, and in disk utility, you can format those two drives as RAID so that Mac OS X essentially sees just one big ass FW800 drive.
this is why you would do RAID in a high-end environment
for your needs, it could just be a fun thing to try out
i have not personally tried it so i may have to investigate, but it may be possible that Mac OS x disk utility allows you to properly do 'redundant' data writing, that means that even if one drive fails, the other still holds most if not all (?) of your data since data is duplicated across the multiple drives and the RAID controller (software or hardware) is supposed to be smart enough, in the higher-end stuff, to allow hot-swaps of drives, etc, etc. like i said, hey, maybe i found myself a weekend project here.
..................
edit: this is a good example of when DOING RAID IS JUST PLAIN SILLY
Open Disk Utility and click the RAID tab. Drag the disks or volumes you want to use into the Disk list, and choose a scheme from the RAID Scheme pop-up menu.
Raid works with both SCSI and IDE/ATA hard drives. Both drives in the RAID must either be SCSI, or IDE/ATA. You cannot combine IDE/ATA with SCSI in a RAID.
There are two basic types of RAIDs.
"Striped" This is where you take two hard drives and combine them together to make one larger drive. This also speeds up the drives, as half of the information is written to each drive.
"Mirrored" This is where you have two hard drives with the exact same data. When a file is modified on one drive, the other is modified to mirror the original drive. When you mirror drives all drives should be the same size as the smallest drive is the size that all the drives use. Any additional space is unused and can not be accessed.
audiopollution or others could chime in, my current feeling is that if you do the multi-bay thing with FW800 then raid is an interesting option.
something to read up and geek out on, this whole RAID thing
if i am not mistaken, the key is the RAID controller, which is either software based (disk utility in mac os X) or hardware based (more expensive expansion bay set ups).
again, just throwing an idea out there, lets say a FW800 expansion bay thingy, throw two or three 7200rpm 8mb cache 3.5" 100+Gb drives in there, and in disk utility, you can format those two drives as RAID so that Mac OS X essentially sees just one big ass FW800 drive.
this is why you would do RAID in a high-end environment
for your needs, it could just be a fun thing to try out
i have not personally tried it so i may have to investigate, but it may be possible that Mac OS x disk utility allows you to properly do 'redundant' data writing, that means that even if one drive fails, the other still holds most if not all (?) of your data since data is duplicated across the multiple drives and the RAID controller (software or hardware) is supposed to be smart enough, in the higher-end stuff, to allow hot-swaps of drives, etc, etc. like i said, hey, maybe i found myself a weekend project here.
..................
edit: this is a good example of when DOING RAID IS JUST PLAIN SILLY
Open Disk Utility and click the RAID tab. Drag the disks or volumes you want to use into the Disk list, and choose a scheme from the RAID Scheme pop-up menu.
Raid works with both SCSI and IDE/ATA hard drives. Both drives in the RAID must either be SCSI, or IDE/ATA. You cannot combine IDE/ATA with SCSI in a RAID.
There are two basic types of RAIDs.
"Striped" This is where you take two hard drives and combine them together to make one larger drive. This also speeds up the drives, as half of the information is written to each drive.
"Mirrored" This is where you have two hard drives with the exact same data. When a file is modified on one drive, the other is modified to mirror the original drive. When you mirror drives all drives should be the same size as the smallest drive is the size that all the drives use. Any additional space is unused and can not be accessed.
~~~~~~
......
Man, the things i am learning -- with a bit of help from y'all !!
At the very least, the mirrored RAID of two disks would seem to be a simple, painless way to make a local backup that would protect against disk corruption that arose from mechanical failure. That wasn't the cause of my recent emergency, but it would be as well to be prepared; I have been using Retrospect and DVD-RWs so far for backup, but Retrospect let me down when it came to the crunch (some of the files on the backup discs weren't readable) and anyway the sheer size of backups for digital photos, video etc. is rapidly outstripping the capacity of removable media', be it DVD or tape.
And now you explain it, striped RAID is very enticing. Except like you, i wonder what happens if one drive fails -- or even if you just want to replace one drive because it's old, or you want to swap it for a bigger one as the price of bigger disks falls and your capacity needds increase. Presumably there must be a way of 'emptying' one disk in a striped RAID stack or array or whatever it's called, for that kind of purpose. if i find out, i'll let you know here.
It is fascinating stuff. Thanks for pointing the way. . . --Angus
Forget about RAIDs for now. You can read up on them and implement one later as you'll have the hardware (and the software in OSX) to do so. In your case, you would want to mirror your drives for backup - rather than having a striped array - since your main concern is data protection.
Get the external enclosure and put your two drives in it.
Call one drive 'External Data 1' or something similar. Call the other drive 'Eternal Backup 1' or something similar.
Don't use the 'External Backup' drive to save your data. Make sure you just save to the 'Eternal Data' drive.
Set up a backup schedule in Retrospect or using to fully back up 'External Data 1' to 'External Backup 1' once a week. You can set it to only copy the changes you've made to the drive, as far as I remember. (You can make the backup interval fewer than 7 days ... it depends on how comfortable you are with losing a finite number of days worth of new files should the data drive fail.)
This way you always have a backup that's no more than 7 days old.
Forget about RAIDs for now. You can read up on them and implement one later as you'll have the hardware (and the software in OSX) to do so. In your case, you would want to mirror your drives for backup - rather than having a striped array - since your main concern is data protection.
Get the external enclosure and put your two drives in it.
Call one drive 'External Data 1' or something similar. Call the other drive 'Eternal Backup 1' or something similar.
Don't use the 'External Backup' drive to save your data. Make sure you just save to the 'Eternal Data' drive.
Set up a backup schedule in Retrospect or using to fully back up 'External Data 1' to 'External Backup 1' once a week. You can set it to only copy the changes you've made to the drive, as far as I remember. (You can make the backup interval fewer than 7 days ... it depends on how comfortable you are with losing a finite number of days worth of new files should the data drive fail.)
This way you always have a backup that's no more than 7 days old.
yesss.... wise and leet audiopollution has suggested a great pre-RAID-mirroring solution to get started with.
...angus... yeah, i'm not to sure about the whole DVD dual-layer thing, i think i'm willing to just skip that whole shebang and go straight to blu-ray or whatever for optical backups, otherwise double-backups to hard disks is the good solution for data integrity.
audiopollution...the thing that grabs me about mirrored raid is that you do essentially just one backup and the hardware (or os X disk utility) gives that piece of mind that every single bit of data is kind of checked twice and stored twice for all reads and writes ... or at least to my simple understanding that's how it makes me feel good.
i actually dropped a 1-month-old maxtor 160gb 7200rpm on the floor the other day, and i was like, hmm.... SMART says its doing okay since then, and chkdsk on windoze found just a few bad sectors, but my trust in it has gone out the window (heh... pun not intended but it seems to work)
This thread makes me want to do a good up-to-date backup.
Meanwhile, here's another interesting question... Can I create a RAID set with just a single partition on large drive? The reason I ask is that I have two drives in my G5, my original 160 GB and a 300 GB I added. I'd like to partition the 300 and setup one partition to mirror with the other drive via RAID 1. I'd have 160 GB of redundant storage plus another 140 GB of extra storage for less-critical files.
This thread makes me want to do a good up-to-date backup.
Meanwhile, here's another interesting question... Can I create a RAID set with just a single partition on large drive? The reason I ask is that I have two drives in my G5, my original 160 GB and a 300 GB I added. I'd like to partition the 300 and setup one partition to mirror with the other drive via RAID 1. I'd have 160 GB of redundant storage plus another 140 GB of extra storage for less-critical files.
OMFG That is a fucking brilliant idea. That is SO what I could do with the 'compromised' 160gb 7200rpm maxtor. Make it into two partitions, giving a nice chunky double-redundant 70+GB backup RAID driveset. Or, if I'm feeling extra paranoid, triple-redundant with three partitions for a 50+GB backup RAID driveset.
Wow, *shakes fist* damn you SF Bay Area kids, always thinking outside the box. Come to think of it, you probably never heard of or seen this 'box' thing
Hmm.. Okay I should be able to test this out in several hours time when my dad comes back from his clinic i am so so close to getting my own Mac
I aim to have a report on my experience with this on 10.4.2, using Disk Utility to RAID, FW400 to IDE bridge GL711 chipset, Maxtor Diamondmax Plus 9 7200rpm 2mb cache 3.5"
(edit: i'll try and do a quick-and-dirty benchmark as well, one with one large .vob file and one with a whole bunch of files from the Applications folder or something)
Of course, the caveat is that if the drive completely fails or that one piece of hardware dies your screwed**, but as opposed to having to buy a second drive and a second drive enclosure, or a multi-bay enclosure, this really might be a good way for me to put that 1 drive through its paces to see how the data integrity holds up. If the drive completely dies, not a problem, since my critical stuff is on the iBook hard disk anyway, and core stuff (contacts, mail, calendar, etc.) is all on .Mac. I pull some CDRWs of the super critical non-.Mac stuff every month anyway, so...
Hmm cool... Why are we so obsessed with backing up? Is it 'normal' to be so jazzed up about this sort of stuff? heh...
I guess we've all learnt through hard personal experience of losing data at the very worst times possible. Particularly now that a good-running Mac is so important for day-to-day work and play.
**(edit2: xool i re-read your post and get your drift now... i might also try partitioning off some of the 160gb external and mirror raid that with my iPod mini just to see how that pans out. in your case, mirroring across two hard drives that way is a good idea)
you can basically make multiple raid sets out of multiple logical or physical drives and partitions. slice and dice any way you want. just for example:
okay so i partitioned my 160gb 7200rpm 'compromised' maxtor into 2 partitions and made that a mirrored raid.
speeds are good, in that the bottleneck is
10MB/sec average coming off the 4200rpm iBook 40gb drive.
write speeds are as one would expect, showing as
20MB/sec average onto the maxtor
Erm ... if you're running a mirrored RAID on two partitions of the same drive your write performance will be cut in half.
I'm also not sure what the point of doing so is, except that it's a neat trick. If the drive fails, rather than a pile of sectors (which hopefully wouldn't span enough of the drive to affect both partitions), the whole point of having a mirrored RAID is down the drain.
Forget about RAIDs for now. You can read up on them and implement one later as you'll have the hardware (and the software in OSX) to do so. In your case, you would want to mirror your drives for backup - rather than having a striped array - since your main concern is data protection.
Get the external enclosure and put your two drives in it.
Call one drive 'External Data 1' or something similar. Call the other drive 'Eternal Backup 1' or something similar.
Don't use the 'External Backup' drive to save your data. Make sure you just save to the 'Eternal Data' drive.
Set up a backup schedule in Retrospect or using to fully back up 'External Data 1' to 'External Backup 1' once a week. You can set it to only copy the changes you've made to the drive, as far as I remember. (You can make the backup interval fewer than 7 days ... it depends on how comfortable you are with losing a finite number of days worth of new files should the data drive fail.)
This way you always have a backup that's no more than 7 days old.
That is very sensible. I may have been getting carried away with the RAID thing.
And I think 'eternal data' is much more optimistic than 'external data', so that's what i'm going to call it
If I can figure out how it's done, would you have any problem with my installing the two HDs internally in the spare bays of my G4 rather than in the external enclosure? I don't mean to be cheap, but 129 bucks is 129 bucks. . . . .
That is very sensible. I may have been getting carried away with the RAID thing.
And I think 'eternal data' is much more optimistic than 'external data', so that's what i'm going to call it
If I can figure out how it's done, would you have any problem with my installing the two HDs internally in the spare bays of my G4 rather than in the external enclosure? I don't mean to be cheap, but 129 bucks is 129 bucks. . . . .
Installing them internally is just fine. Save the bucks!
Erm ... if you're running a mirrored RAID on two partitions of the same drive your write performance will be cut in half.
I'm also not sure what the point of doing so is, except that it's a neat trick. If the drive fails, rather than a pile of sectors (which hopefully wouldn't span enough of the drive to affect both partitions), the whole point of having a mirrored RAID is down the drain.
I'd be careful!
I agree. If you make a RAID with two partitions on the same drive you're not getting much benefit as far as redundancy (if the drive dies you still lose all your data) and you also take a speed hit as both writes have to happen to the same drive rather than happening in parallel to separate drives.
I think my idea mentioned a few posts above will work though and makes the best use of my current storage. The one problem is setting it up... I need an extra place for my data while I repartition the large drive. If I can fit it all on my smaller drive I'd be OK. Time for some HD spring cleaning.
Thanks. By the way, do you put any stock in disk maintainance utilities like Disk Warrior, or should OS X's disk-monitoring be enough?
It can't hurt, but I've never used them.
Actually, on second thought, it could hurt and I am only speaking from my recollection of the tales told of Norton Utilities. Disk Warrior seems to be well spoken of. Hopefully someone else here can give you some more feedback about it.
I've had good experiences with Disk Warrior and Tech Tool Pro. However, a version of Tech Tool comes with AppleCare and might be enough for your needs. My general go-to utility is still Apple's Disk Utility.
Erm ... if you're running a mirrored RAID on two partitions of the same drive your write performance will be cut in half.
I'm also not sure what the point of doing so is, except that it's a neat trick. If the drive fails, rather than a pile of sectors (which hopefully wouldn't span enough of the drive to affect both partitions), the whole point of having a mirrored RAID is down the drain.
I'd be careful!
fair enough, i think its just a bit of a fun hack for me for now, if the drive dies i still have like i mentioned, from most to least critical, backups on .Mac, CDRW, the iBook hard disk itself.
like i said i dropped the drive and chkdsk windows shows a few bad sectors, 4kb or so, so just doing the RAID thing helps me emotionally, that, hey, well, i can still use this one-month-old drive to backup stuff and i prefer having the RAID software mirroring thing as something extra to warn me if the disk is dying, rather than a generic Finder error.
yup, write performance is cut in half, but i think it looks like, 10mbytes/sec is the maximum average read speed coming off the 4200rpm 2.5" iBook drive. the bottleneck is the read of the iBook drive, not the mirrored drive \
Comments
something to read up and geek out on, this whole RAID thing
if i am not mistaken, the key is the RAID controller, which is either software based (disk utility in mac os X) or hardware based (more expensive expansion bay set ups).
again, just throwing an idea out there, lets say a FW800 expansion bay thingy, throw two or three 7200rpm 8mb cache 3.5" 100+Gb drives in there, and in disk utility, you can format those two drives as RAID so that Mac OS X essentially sees just one big ass FW800 drive.
this is why you would do RAID in a high-end environment
http://www.apple.com/xserve/raid/
for your needs, it could just be a fun thing to try out
i have not personally tried it so i may have to investigate, but it may be possible that Mac OS x disk utility allows you to properly do 'redundant' data writing, that means that even if one drive fails, the other still holds most if not all (?) of your data since data is duplicated across the multiple drives and the RAID controller (software or hardware) is supposed to be smart enough, in the higher-end stuff, to allow hot-swaps of drives, etc, etc. like i said, hey, maybe i found myself a weekend project here.
..................
edit: this is a good example of when DOING RAID IS JUST PLAIN SILLY
iPod Shuffle RAID
http://www.wrightthisway.com/Articles/000154.html
...................
edit2: here's what i was kinda talking about
http://support.clubmac.com/display.asp?r=518
~~~~~
Open Disk Utility and click the RAID tab. Drag the disks or volumes you want to use into the Disk list, and choose a scheme from the RAID Scheme pop-up menu.
Raid works with both SCSI and IDE/ATA hard drives. Both drives in the RAID must either be SCSI, or IDE/ATA. You cannot combine IDE/ATA with SCSI in a RAID.
There are two basic types of RAIDs.
"Striped" This is where you take two hard drives and combine them together to make one larger drive. This also speeds up the drives, as half of the information is written to each drive.
"Mirrored" This is where you have two hard drives with the exact same data. When a file is modified on one drive, the other is modified to mirror the original drive. When you mirror drives all drives should be the same size as the smallest drive is the size that all the drives use. Any additional space is unused and can not be accessed.
~~~~~~
......
found out about my fw400/usb2.0 to IDE 3.5" enclosure. uses the GL711 chipset, which is popping up in places instead of the Oxford911 chipset.
so far, i would have to say, no problems with GL711 chipset
linky:
http://www.genesyslogic.com/econtent...stcidx=3&SN=33
Originally posted by sunilraman
audiopollution or others could chime in, my current feeling is that if you do the multi-bay thing with FW800 then raid is an interesting option.
something to read up and geek out on, this whole RAID thing
if i am not mistaken, the key is the RAID controller, which is either software based (disk utility in mac os X) or hardware based (more expensive expansion bay set ups).
again, just throwing an idea out there, lets say a FW800 expansion bay thingy, throw two or three 7200rpm 8mb cache 3.5" 100+Gb drives in there, and in disk utility, you can format those two drives as RAID so that Mac OS X essentially sees just one big ass FW800 drive.
this is why you would do RAID in a high-end environment
http://www.apple.com/xserve/raid/
for your needs, it could just be a fun thing to try out
i have not personally tried it so i may have to investigate, but it may be possible that Mac OS x disk utility allows you to properly do 'redundant' data writing, that means that even if one drive fails, the other still holds most if not all (?) of your data since data is duplicated across the multiple drives and the RAID controller (software or hardware) is supposed to be smart enough, in the higher-end stuff, to allow hot-swaps of drives, etc, etc. like i said, hey, maybe i found myself a weekend project here.
..................
edit: this is a good example of when DOING RAID IS JUST PLAIN SILLY
iPod Shuffle RAID
http://www.wrightthisway.com/Articles/000154.html
...................
edit2: here's what i was kinda talking about
http://support.clubmac.com/display.asp?r=518
~~~~~
Open Disk Utility and click the RAID tab. Drag the disks or volumes you want to use into the Disk list, and choose a scheme from the RAID Scheme pop-up menu.
Raid works with both SCSI and IDE/ATA hard drives. Both drives in the RAID must either be SCSI, or IDE/ATA. You cannot combine IDE/ATA with SCSI in a RAID.
There are two basic types of RAIDs.
"Striped" This is where you take two hard drives and combine them together to make one larger drive. This also speeds up the drives, as half of the information is written to each drive.
"Mirrored" This is where you have two hard drives with the exact same data. When a file is modified on one drive, the other is modified to mirror the original drive. When you mirror drives all drives should be the same size as the smallest drive is the size that all the drives use. Any additional space is unused and can not be accessed.
~~~~~~
......
Man, the things i am learning -- with a bit of help from y'all !!
At the very least, the mirrored RAID of two disks would seem to be a simple, painless way to make a local backup that would protect against disk corruption that arose from mechanical failure. That wasn't the cause of my recent emergency, but it would be as well to be prepared; I have been using Retrospect and DVD-RWs so far for backup, but Retrospect let me down when it came to the crunch (some of the files on the backup discs weren't readable) and anyway the sheer size of backups for digital photos, video etc. is rapidly outstripping the capacity of removable media', be it DVD or tape.
And now you explain it, striped RAID is very enticing. Except like you, i wonder what happens if one drive fails -- or even if you just want to replace one drive because it's old, or you want to swap it for a bigger one as the price of bigger disks falls and your capacity needds increase. Presumably there must be a way of 'emptying' one disk in a striped RAID stack or array or whatever it's called, for that kind of purpose. if i find out, i'll let you know here.
It is fascinating stuff. Thanks for pointing the way. . . --Angus
Forget about RAIDs for now. You can read up on them and implement one later as you'll have the hardware (and the software in OSX) to do so. In your case, you would want to mirror your drives for backup - rather than having a striped array - since your main concern is data protection.
Get the external enclosure and put your two drives in it.
Call one drive 'External Data 1' or something similar. Call the other drive 'Eternal Backup 1' or something similar.
Don't use the 'External Backup' drive to save your data. Make sure you just save to the 'Eternal Data' drive.
Set up a backup schedule in Retrospect or using to fully back up 'External Data 1' to 'External Backup 1' once a week. You can set it to only copy the changes you've made to the drive, as far as I remember. (You can make the backup interval fewer than 7 days ... it depends on how comfortable you are with losing a finite number of days worth of new files should the data drive fail.)
This way you always have a backup that's no more than 7 days old.
Originally posted by audiopollution
Here's what I would do in your position.
Forget about RAIDs for now. You can read up on them and implement one later as you'll have the hardware (and the software in OSX) to do so. In your case, you would want to mirror your drives for backup - rather than having a striped array - since your main concern is data protection.
Get the external enclosure and put your two drives in it.
Call one drive 'External Data 1' or something similar. Call the other drive 'Eternal Backup 1' or something similar.
Don't use the 'External Backup' drive to save your data. Make sure you just save to the 'Eternal Data' drive.
Set up a backup schedule in Retrospect or using to fully back up 'External Data 1' to 'External Backup 1' once a week. You can set it to only copy the changes you've made to the drive, as far as I remember. (You can make the backup interval fewer than 7 days ... it depends on how comfortable you are with losing a finite number of days worth of new files should the data drive fail.)
This way you always have a backup that's no more than 7 days old.
yesss.... wise and leet audiopollution has suggested a great pre-RAID-mirroring solution to get started with.
...angus... yeah, i'm not to sure about the whole DVD dual-layer thing, i think i'm willing to just skip that whole shebang and go straight to blu-ray or whatever for optical backups, otherwise double-backups to hard disks is the good solution for data integrity.
audiopollution...the thing that grabs me about mirrored raid is that you do essentially just one backup and the hardware (or os X disk utility) gives that piece of mind that every single bit of data is kind of checked twice and stored twice for all reads and writes ... or at least to my simple understanding that's how it makes me feel good.
i actually dropped a 1-month-old maxtor 160gb 7200rpm on the floor the other day, and i was like, hmm.... SMART says its doing okay since then, and chkdsk on windoze found just a few bad sectors, but my trust in it has gone out the window (heh... pun not intended but it seems to work)
Meanwhile, here's another interesting question... Can I create a RAID set with just a single partition on large drive? The reason I ask is that I have two drives in my G5, my original 160 GB and a 300 GB I added. I'd like to partition the 300 and setup one partition to mirror with the other drive via RAID 1. I'd have 160 GB of redundant storage plus another 140 GB of extra storage for less-critical files.
Originally posted by Xool
This thread makes me want to do a good up-to-date backup.
Meanwhile, here's another interesting question... Can I create a RAID set with just a single partition on large drive? The reason I ask is that I have two drives in my G5, my original 160 GB and a 300 GB I added. I'd like to partition the 300 and setup one partition to mirror with the other drive via RAID 1. I'd have 160 GB of redundant storage plus another 140 GB of extra storage for less-critical files.
OMFG That is a fucking brilliant idea. That is SO what I could do with the 'compromised' 160gb 7200rpm maxtor. Make it into two partitions, giving a nice chunky double-redundant 70+GB backup RAID driveset. Or, if I'm feeling extra paranoid, triple-redundant with three partitions for a 50+GB backup RAID driveset.
Wow, *shakes fist* damn you SF Bay Area kids, always thinking outside the box. Come to think of it, you probably never heard of or seen this 'box' thing
Hmm.. Okay I should be able to test this out in several hours time when my dad comes back from his clinic
I aim to have a report on my experience with this on 10.4.2, using Disk Utility to RAID, FW400 to IDE bridge GL711 chipset, Maxtor Diamondmax Plus 9 7200rpm 2mb cache 3.5"
(edit: i'll try and do a quick-and-dirty benchmark as well, one with one large .vob file and one with a whole bunch of files from the Applications folder or something)
Of course, the caveat is that if the drive completely fails or that one piece of hardware dies your screwed**, but as opposed to having to buy a second drive and a second drive enclosure, or a multi-bay enclosure, this really might be a good way for me to put that 1 drive through its paces to see how the data integrity holds up. If the drive completely dies, not a problem, since my critical stuff is on the iBook hard disk anyway, and core stuff (contacts, mail, calendar, etc.) is all on .Mac. I pull some CDRWs of the super critical non-.Mac stuff every month anyway, so...
Hmm cool... Why are we so obsessed with backing up? Is it 'normal' to be so jazzed up about this sort of stuff? heh...
I guess we've all learnt through hard personal experience of losing data at the very worst times possible.
**(edit2: xool i re-read your post and get your drift now... i might also try partitioning off some of the 160gb external and mirror raid that with my iPod mini just to see how that pans out. in your case, mirroring across two hard drives that way is a good idea)
you can basically make multiple raid sets out of multiple logical or physical drives and partitions. slice and dice any way you want. just for example:
speeds are good, in that the bottleneck is
10MB/sec average coming off the 4200rpm iBook 40gb drive.
write speeds are as one would expect, showing as
20MB/sec average onto the maxtor
this is through the FW400 to IDE bridge with GL711 chip as i mentioned before.
overall, this gives me at this stage quite a lot of peace of mind,
knowing that the RAID software is making sure the data in and out of the external drive is clean.
being double redundant, if the RAID software hits a bad sector on one mirror it should be smart enough to deal with it by using the other partition
in any case, if my house burns down, hopefully the two CDRWs of important stuff will survive
Originally posted by sunilraman
okay so i partitioned my 160gb 7200rpm 'compromised' maxtor into 2 partitions and made that a mirrored raid.
speeds are good, in that the bottleneck is
10MB/sec average coming off the 4200rpm iBook 40gb drive.
write speeds are as one would expect, showing as
20MB/sec average onto the maxtor
Erm ... if you're running a mirrored RAID on two partitions of the same drive your write performance will be cut in half.
I'm also not sure what the point of doing so is, except that it's a neat trick. If the drive fails, rather than a pile of sectors (which hopefully wouldn't span enough of the drive to affect both partitions), the whole point of having a mirrored RAID is down the drain.
I'd be careful!
Originally posted by audiopollution
Here's what I would do in your position.
Forget about RAIDs for now. You can read up on them and implement one later as you'll have the hardware (and the software in OSX) to do so. In your case, you would want to mirror your drives for backup - rather than having a striped array - since your main concern is data protection.
Get the external enclosure and put your two drives in it.
Call one drive 'External Data 1' or something similar. Call the other drive 'Eternal Backup 1' or something similar.
Don't use the 'External Backup' drive to save your data. Make sure you just save to the 'Eternal Data' drive.
Set up a backup schedule in Retrospect or using to fully back up 'External Data 1' to 'External Backup 1' once a week. You can set it to only copy the changes you've made to the drive, as far as I remember. (You can make the backup interval fewer than 7 days ... it depends on how comfortable you are with losing a finite number of days worth of new files should the data drive fail.)
This way you always have a backup that's no more than 7 days old.
That is very sensible. I may have been getting carried away with the RAID thing.
And I think 'eternal data' is much more optimistic than 'external data', so that's what i'm going to call it
If I can figure out how it's done, would you have any problem with my installing the two HDs internally in the spare bays of my G4 rather than in the external enclosure? I don't mean to be cheap, but 129 bucks is 129 bucks. . . . .
Originally posted by Angus McCallum
That is very sensible. I may have been getting carried away with the RAID thing.
And I think 'eternal data' is much more optimistic than 'external data', so that's what i'm going to call it
If I can figure out how it's done, would you have any problem with my installing the two HDs internally in the spare bays of my G4 rather than in the external enclosure? I don't mean to be cheap, but 129 bucks is 129 bucks. . . . .
Installing them internally is just fine. Save the bucks!
Originally posted by audiopollution
Erm ... if you're running a mirrored RAID on two partitions of the same drive your write performance will be cut in half.
I'm also not sure what the point of doing so is, except that it's a neat trick. If the drive fails, rather than a pile of sectors (which hopefully wouldn't span enough of the drive to affect both partitions), the whole point of having a mirrored RAID is down the drain.
I'd be careful!
I agree. If you make a RAID with two partitions on the same drive you're not getting much benefit as far as redundancy (if the drive dies you still lose all your data) and you also take a speed hit as both writes have to happen to the same drive rather than happening in parallel to separate drives.
I think my idea mentioned a few posts above will work though and makes the best use of my current storage. The one problem is setting it up... I need an extra place for my data while I repartition the large drive. If I can fit it all on my smaller drive I'd be OK. Time for some HD spring cleaning.
Originally posted by audiopollution
Installing them internally is just fine. Save the bucks!
Thanks. By the way, do you put any stock in disk maintainance utilities like Disk Warrior, or should OS X's disk-monitoring be enough?
Originally posted by Angus McCallum
Thanks. By the way, do you put any stock in disk maintainance utilities like Disk Warrior, or should OS X's disk-monitoring be enough?
It can't hurt, but I've never used them.
Actually, on second thought, it could hurt and I am only speaking from my recollection of the tales told of Norton Utilities. Disk Warrior seems to be well spoken of. Hopefully someone else here can give you some more feedback about it.
Originally posted by audiopollution
Erm ... if you're running a mirrored RAID on two partitions of the same drive your write performance will be cut in half.
I'm also not sure what the point of doing so is, except that it's a neat trick. If the drive fails, rather than a pile of sectors (which hopefully wouldn't span enough of the drive to affect both partitions), the whole point of having a mirrored RAID is down the drain.
I'd be careful!
fair enough, i think its just a bit of a fun hack for me for now, if the drive dies i still have like i mentioned, from most to least critical, backups on .Mac, CDRW, the iBook hard disk itself.
like i said i dropped the drive and chkdsk windows shows a few bad sectors, 4kb or so, so just doing the RAID thing helps me emotionally, that, hey, well, i can still use this one-month-old drive to backup stuff and i prefer having the RAID software mirroring thing as something extra to warn me if the disk is dying, rather than a generic Finder error.
yup, write performance is cut in half, but i think it looks like, 10mbytes/sec is the maximum average read speed coming off the 4200rpm 2.5" iBook drive. the bottleneck is the read of the iBook drive, not the mirrored drive