If I remember correctly from my networking classes desn't hard drive life decrease when the drives are stored and run vertically? I LOVE the design of the RAID but every time I have had a vertical HD it has died like 5 times faster than my horizontal ones.
<strong>If I remember correctly from my networking classes desn't hard drive life decrease when the drives are stored and run vertically? I LOVE the design of the RAID but every time I have had a vertical HD it has died like 5 times faster than my horizontal ones.
Mac Guru</strong><hr></blockquote>
Steve J. himself eluded to this fact when he was talking about the new form-factor for the iMac... he said that drives do not perform as well, nor last as well in a vertical orientation, hence them not using that type of setup in some of the iMac design ideas.
Now all-of-a-sudden, it's okay...?
Hmmmm... I hope he (they) knows (know) something that we don't, because I'm no tech-wizard... but even to ME, it seems like a bad idea... but what do I know...?
At the time he was specifically speaking about CD and DVD drives which do have significant issues on their sides. Those issues restrict the max RPM to something ridiculously low by current standards.
Okay... it's not that I "Doubt" what has been said here about SCSI being faster... but is there any truth to what Apple says about their use of the ATA/100 drives in the Xserve...?
Paste:
"The ATA drive subsystem has a high-bandwidth I/O bus that minimizes bottlenecks, even when all four drives are engaged at once. That?s how Xserve can achieve a theoretical peak performance of up to 266 megabytes per second, compared to a 160MB/s theoretical performance with SCSI Ultra160 disk drives ? at a significantly lower cost, and while generating less heat than SCSI drives."
I know this thread is about the RAID unit... but it's "somewhat" relative.
I think they just used pseudo-science to proclaim that...basically combining the bandwidth of 4 separate ATA/100 channels and getting 4x66.666=266 MB/s vs servers configured with only one Ultra SCSI 160 MB/s controller.
Also, can you get the Apple Drive chassis and install your own drive, or do you need to buy this whole widget from them. <img src="graemlins/smokin.gif" border="0" alt="[Chilling]" />
The problem of ATA vs SCSI is that ATA drives do not come in faster than 7200 RPM models, while SCSI come in 10K and 15K RPM models.
More importantly, a SCSI drive can process requests out of order. If requests for 4 different blocks of data come in, the SCSI drive can fulfill them so as to minimize head movement and spindle latency, ATA drives cannot as they fulfill requests in the order they are placed.
Correct, SCSI shines when multiple threads are accessed in the filesystem, but I think the IDE disadvantage is minimalized by virtue of the brute force...each disk in an Xserve and Xserve RAID is on its own bus...even if real-life throughput will be far short of 266 MB/s.
<strong>Correct, SCSI shines when multiple threads are accessed in the filesystem, but I think the IDE disadvantage is minimalized by virtue of the brute force...each disk in an Xserve and Xserve RAID is on its own bus...even if real-life throughput will be far short of 266 MB/s.
The big question for me is... would I be able to use that product with my G4 to serve-up video & audio if it were striped...?
My "understanding" (which may be wrong) of the configuration is that there are 14 drives... 2 banks of 7, each bank of 7 gets striped together and they mirror each-other, so it's essentially a RAID of 7 drives with another 7 to be a back-up.
If one drive goes... am I hosed with ALL of my data within that bank of 7...? (ignoring the back-up mirror)
Getting back to the horizontal vs. vertical drive mounting in the RAID unit:
The RAID unit is 3U tall. That's enough room for 3, 1U Xserves. How many drives is that? It's 12 (3 times 4). Those would be horizontally mounted and there would be some extra space left over.
Now, of course, I'm not saying get 3 Xserves instead of the RAID, I'm pointing out that it doesn't seem like Apple absolutely had to mount the drives in the RAID unit vertically.
The question is, is there enough extra space in that 3U for at least two more horizontally-mounted drives? We know 12 will fit.
<strong>The big question for me is... would I be able to use that product with my G4 to serve-up video & audio if it were striped...?
My "understanding" (which may be wrong) of the configuration is that there are 14 drives... 2 banks of 7, each bank of 7 gets striped together and they mirror each-other, so it's essentially a RAID of 7 drives with another 7 to be a back-up.
If one drive goes... am I hosed with ALL of my data within that bank of 7...? (ignoring the back-up mirror)
- Scott</strong><hr></blockquote>
The simple answer is do not run RAID 0, for DV and Audio your performance would be fine running RAID 5 or a Combo of Levels(ie 0 +1)
The simple answer is do not run RAID 0, for DV and Audio your performance would be fine running RAID 5 or a Combo of Levels(ie 0 +1)</strong><hr></blockquote>
MAN! Do I need to do some homework, or WHAT...!!!??? All I got from that was "Blah blah blah blah RAID blah blah DV blah Audio blah blah blah performance blah blah..."
This is not a comment on YOU... just MY lack of understanding in this area. I need to go read-up on the subject of RAIDs before asking questions I guess.
It turns out (not mentioned there) that 7 disks is the best number for a RAID 5, as you loose exactly one (hmm perhaps two, I can't remember) disk(s) to the error correction info.
Comments
and make it a 3U and add 10 more drive bays... it's not THAT much bigger.
Mac Guru
[ 05-14-2002: Message edited by: Eugene ]</p>
<strong>The HDDs in the Xserve RAID will be mounted vertically, 14 columns. It's strictly a disk array as well. No G4s, no fancy I/O.
[ 05-14-2002: Message edited by: Eugene ]</strong><hr></blockquote>
And it looks like this:
Mac Guru
<strong>If I remember correctly from my networking classes desn't hard drive life decrease when the drives are stored and run vertically? I LOVE the design of the RAID but every time I have had a vertical HD it has died like 5 times faster than my horizontal ones.
Mac Guru</strong><hr></blockquote>
Steve J. himself eluded to this fact when he was talking about the new form-factor for the iMac... he said that drives do not perform as well, nor last as well in a vertical orientation, hence them not using that type of setup in some of the iMac design ideas.
Now all-of-a-sudden, it's okay...?
Hmmmm... I hope he (they) knows (know) something that we don't, because I'm no tech-wizard... but even to ME, it seems like a bad idea... but what do I know...?
- Scott
<strong>
At the time he was specifically speaking about CD and DVD drives which do have significant issues on their sides. Those issues restrict the max RPM to something ridiculously low by current standards.
[ 05-14-2002: Message edited by: AirSluf ]</strong><hr></blockquote>
AAaaahh! That must have been it... my mistake. Sometimes I hear what I want to hear.
Thanks for the info.
<strong>
And it looks like this:
A similar setup to many raid boxes I have seen. Like the IBM EXP15. Only much purtier...
[ 05-14-2002: Message edited by: RazzFazz ]</p>
Paste:
"The ATA drive subsystem has a high-bandwidth I/O bus that minimizes bottlenecks, even when all four drives are engaged at once. That?s how Xserve can achieve a theoretical peak performance of up to 266 megabytes per second, compared to a 160MB/s theoretical performance with SCSI Ultra160 disk drives ? at a significantly lower cost, and while generating less heat than SCSI drives."
I know this thread is about the RAID unit... but it's "somewhat" relative.
More importantly, a SCSI drive can process requests out of order. If requests for 4 different blocks of data come in, the SCSI drive can fulfill them so as to minimize head movement and spindle latency, ATA drives cannot as they fulfill requests in the order they are placed.
[ 05-15-2002: Message edited by: Eugene ]</p>
<strong>Correct, SCSI shines when multiple threads are accessed in the filesystem, but I think the IDE disadvantage is minimalized by virtue of the brute force...each disk in an Xserve and Xserve RAID is on its own bus...even if real-life throughput will be far short of 266 MB/s.
[ 05-15-2002: Message edited by: Eugene ]</strong><hr></blockquote>
not to mention cost.
My "understanding" (which may be wrong) of the configuration is that there are 14 drives... 2 banks of 7, each bank of 7 gets striped together and they mirror each-other, so it's essentially a RAID of 7 drives with another 7 to be a back-up.
If one drive goes... am I hosed with ALL of my data within that bank of 7...? (ignoring the back-up mirror)
- Scott
The RAID unit is 3U tall. That's enough room for 3, 1U Xserves. How many drives is that? It's 12 (3 times 4). Those would be horizontally mounted and there would be some extra space left over.
Now, of course, I'm not saying get 3 Xserves instead of the RAID, I'm pointing out that it doesn't seem like Apple absolutely had to mount the drives in the RAID unit vertically.
The question is, is there enough extra space in that 3U for at least two more horizontally-mounted drives? We know 12 will fit.
<strong>The big question for me is... would I be able to use that product with my G4 to serve-up video & audio if it were striped...?
My "understanding" (which may be wrong) of the configuration is that there are 14 drives... 2 banks of 7, each bank of 7 gets striped together and they mirror each-other, so it's essentially a RAID of 7 drives with another 7 to be a back-up.
If one drive goes... am I hosed with ALL of my data within that bank of 7...? (ignoring the back-up mirror)
- Scott</strong><hr></blockquote>
The simple answer is do not run RAID 0, for DV and Audio your performance would be fine running RAID 5 or a Combo of Levels(ie 0 +1)
<strong>
The simple answer is do not run RAID 0, for DV and Audio your performance would be fine running RAID 5 or a Combo of Levels(ie 0 +1)</strong><hr></blockquote>
MAN! Do I need to do some homework, or WHAT...!!!??? All I got from that was "Blah blah blah blah RAID blah blah DV blah Audio blah blah blah performance blah blah..."
This is not a comment on YOU... just MY lack of understanding in this area. I need to go read-up on the subject of RAIDs before asking questions I guess.
Thanx anyhow.
It turns out (not mentioned there) that 7 disks is the best number for a RAID 5, as you loose exactly one (hmm perhaps two, I can't remember) disk(s) to the error correction info.
[ 05-15-2002: Message edited by: *l++ ]</p>