New Blood (xRAID Thread)

in Future Apple Hardware edited January 2014
Just thought I'd offer a little new blood to the forum. I don't post on BB's often but have enjoyed reading the speculation on these pages a great deal. I'm just a bit tired of the same G5, PDA, iDevice, etc threads that dominate this forum.

That 'bout something new?

Apple has announced its 'xRAID' rack mount raid array. The xRAID should be released (if memory serves)by the end of the year to compliment its xServe product. xRAID reportedly supports 2gb fibre channel I/O. Will Apple release its own fibre channel card for the interface or go to a third party vendor such as Atto? Will Apple add native support for this card Jagwire so that an xRAID may be used with a standard PowerMac?

With all of the talk of a 'new' or 'next-generation' PowerMac or even a workstation class machine, as well as Apple's recent forrays into high-end 3D and video, I think this discussion becomes very relevant. I personally work in Audio, Video and Graphic Design and would love to have 1.68 TB in a 3U, Apple branded AND supported package. Anyone who has had to deal with finding third party large format data solutions knows what I'm talking about.

Anyway, enough rambling! I'd love to hear any opinions, speculation, et al.


  • Reply 1 of 28
    hmurchisonhmurchison Posts: 12,375member
    I think Xraid is gonna kick glutes. I hope it support ATA 133 though so that eventually the option exists for drives larger than 137GB. If it has Fibre Channel you know it's going to be fast. Am I correct in assuming that each drive will be on a dedicated channel?
  • Reply 2 of 28
    othelloothello Posts: 1,054member
    Its odd that the xRAID hasn't been talked about that much. Especially when its one of the coolest things Apple has done in a while.

    OK, its only cool for a certain type of user, but for that user it *rocks*
  • Reply 3 of 28
    nagrommenagromme Posts: 2,834member
    Xserve RAID is certainly for real and pretty far along, judging by the photos (3U) Apple has released of it. But I missed the actual announcement. I thought it was a CPU/server like an Xserve, but with hardware RAID (and 14 drives instead of 4). But the thing seems to have no CD-ROM... so is it actually a "peripheral" add-on for an Xserve? Or does it have its own CPU to stand alone, as I originally thought? I can't see the ports clearly, and I can't tell if it's got CPU lights on the front, or just vents. But I'm thinking the thing may be just a RAID, not a server in its own right. Nothing wrong with that! Confirmation?
  • Reply 4 of 28
    macroninmacronin Posts: 1,174member
    Just a RAID unit...

    No CPUs here, move along...
  • Reply 5 of 28
    will each drive get its own channel? what raid levels will it support? do the xserves already have a fibre channel connection or will it be an add on card? will it just be fibre channel or will scsi be an option? how will you setup the raid levels? price? do you have to buy hard drives from apple?
  • Reply 6 of 28
    nevynnevyn Posts: 360member
    [quote]Originally posted by dartblazer:

    <strong>will each drive get its own channel? what raid levels will it support? do the xserves already have a fibre channel connection or will it be an add on card? will it just be fibre channel or will scsi be an option? how will you setup the raid levels? price? do you have to buy hard drives from apple?</strong><hr></blockquote>

    From the MWNY keynote, I can recall this:

    A 3U rackmounted widget with the drives mounted 'vertically' 14-across when fully populated. Visually it looks like 14 books on a shelf. Same mechanism for those drives as for the XServe's drives -&gt; probably have to buy the whole drive + carrier from Apple.

    Seven drives hook interface to one FibreChannel cable, seven to the other FC cable. 'Supports RAID 0,1,3?,5' I think it mentioned several higher levels of RAID, but I can't remember which.

    I think it would be just FibreChannel.

    I have no idea what the price would be, it wasn't mentioned. The drives will be hideously expensive though
  • Reply 7 of 28
    phishyphishy Posts: 34member
    Just in case

  • Reply 8 of 28
    Think apple's margins will be high enough on it to lower the prices of PowerMacs?
  • Reply 9 of 28
    macubusmacubus Posts: 95member
    [quote]Originally posted by MicrosoftOsXp:

    <strong>Think apple's margins will be high enough on it to lower the prices of PowerMacs? </strong><hr></blockquote>

    We'll see if they upgrade the 'power'macs for people to buy them in the first place. I've got about 2700 dollars saved just in case. <img src="graemlins/smokin.gif" border="0" alt="[Chilling]" />
  • Reply 10 of 28
    A few details about the announced Xserve RAID that I learned at a recent Apple Xserve/Jaguar Server Training:

    14 vertical Drive bays using identical drive modules as the Xserve, so you can swap them back and forth as you like. (You can get an Xserve and grow with it, then move your drives to the RAID if you still need more space.) It's 3U in size (and will not have an option for a CD-ROM to answer nagromme's question.)

    The drive modules will still feature ATA 100 and not ATA133. This is NOT a tragedy as most of you thing in terms of drive size. Apple implements the (now industry standard I guess) maxtor protocol for "big drive support" allowing sizes over 128GB mathematical/137GB marketing speech. (2^10 vs. 10^3) Apple CAN move to ATA133 should drives become available that can MAX OUT an ATA100 interface in terms of transfer. Since every drive bay has it's own ATA channel there's no payload for managing master and slaves. There's no need to make the interface faster if nobody can use it. ATA133 is still more expensive to implement and using Maxor protocol drive size (read 48bit adressing) is not an issue anymore.

    It will have DUAL Fiber Channel. (3.2 Gbit/s) This will gurantee for a sustained data rate of 200MB/s at ANY RAID level. Fiber Channel will also allow to connect hte RAID to more than one Xserve simultanously.

    Dual redundant power supplies that will be hot swappable.

    Basically everything will be redundant.

    The backplane of the RAID will have nearly no components mounted so the possibility of blowing your backplane is approximating zero.

    SCSI will no be an option, doesn't make sense here. There's a reason why Apple uses ATA instead of SCSI here. I can elaborate on the architecture behind that if requested.

    The RAID will have a CPU as it does all the RAID calculations in hardware and NOT software like the Xserve does. This processor will also allow for life rebuilds during runtime.

    Supported RAID levels allow for almost anything you could imagine. Ranging from 0-50. I'm not sure about L60.

    You will have to buy modules form Apple becuase the drives are specially selected for several reasons. (heat and support for SMART by the monitor application) You can't get "empty modules" to fit in your own drives. Because of the reasons mentioned above I cannot recommend that as well.

    As for pricing I can only guess. No numbers here, but in comparison to what the competition offers in SCSI variants it will surely be extremely competitive in price/value/size.
  • Reply 11 of 28
    whisperwhisper Posts: 735member
    [quote]Originally posted by monsterjaeger:

    <strong>SCSI will no be an option, doesn't make sense here. There's a reason why Apple uses ATA instead of SCSI here. I can elaborate on the architecture behind that if requested.</strong><hr></blockquote>

    I thought SCSI drives were faster than ATA drives. Does this xRAID thing provide its own ATA controller somehow? Yes, please elaborate.
  • Reply 12 of 28
    rhumgodrhumgod Posts: 1,289member
    [quote]Originally posted by Whisper:

    <strong>I thought SCSI drives were faster than ATA drives. Does this xRAID thing provide its own ATA controller somehow? Yes, please elaborate.</strong><hr></blockquote>

    SCSI drives have better sustained throughput, but the cost is way out there. The RAID controller is the piece you were missing and is indeed ATA - I believe I remember the announcement about an XServe RAID model (server model with raid). Not sure if they plan on releasing just a controller, but I cannot imagine not.
  • Reply 13 of 28
    tabootaboo Posts: 128member
    Yep. I would assume that cost is THE big factor.

    I run a 3 drive U160 (at U2W - older PCI restrictions) raid in my 9600, and it is PDQ.

    However, an 18gig cheetah costs me 'bout $210USD, not including taxes, shipping, etc - and that's only for 18gig. You don't even wanna think about the cost of the faster (15000rpm) cheetahs, or the bigger sizes in multiples. It's kinda sick compared to ATA.

    At current prices, a 73gig cheetah (currently the largest available) is 'bout $600, and a 180gig barracuda is 'bout $1400. For one. Yes, other manufacturers are cheaper, but seagate has the best (read longest - 5 year) warranty, and the lowest MTBF.
  • Reply 14 of 28
    my scsi question was not for the drives but for the interface to connect to the xserve. but i assume that wont be an option?
  • Reply 15 of 28
    noexitnoexit Posts: 20member
    wow thats cool!!

    hmmm.. and why am i only hearing about this now?? <img src="graemlins/hmmm.gif" border="0" alt="[Hmmm]" />

    damn that thing looks sexy!!
  • Reply 16 of 28
    Ok, I hope to answer all questions that arose...

    It's common misbelieve that SCSI drives are faster than ATA drives. Fact is, that manufacturers use the identical drive mechanics in SCSI and ATA drives. It's only the controllers that are different. There are currently no drives that can max out even an ATA66 or any faster interface with sustained transfer rates. Bursts from the drive's cache might but only for a very short time. Since a usual file access involves accessing directory and file data this effect is mostly viible when writing small files but not for a long time.

    What is indeed different and in favor of SCSI is the nominal speed of the interface. With SCSI topping at 160MB/s and ATA at 133/100. The main difference between the interfaces is that SCSI handles all the drives via the controller on the bus. Whereas ATA needs some processing power to manage the bus when there's more than one dive connected. (Master/Slave config) Therefor an ATA bus usually slows down when you connect a second drive and especially when copying from master to slave or vice versa. (It's similar to the ethernet hub vs. switch problem) On the other hand the SCSI Bus is vulnerable to malicious SCSI signal bursts generated by a defective controller. This usually slows down the chain, often bringing transfer to a halt or damaging data. ATA is less vulnerabel to this problems. There's also a simple splution to this when using ATA. Give each drive it's own bus. This gives you maximum security as a defective controller can't disturb other drives, maxes throughput to the mechanics possible maximum and doesn't eat processin power since there's no need for master/slave management on the bus. Due to much lower prices for ATA controllers this solution has many advantages over a SCSI chain.

    Additional benefit comes from the possibility to hot-plug an ATA drive. SCSI does not allow this by specification. (Power down, alter chain, power up again. I know many ppl to hot plug SCSI devices, but that's definitely not suitable for critical data on your server setup. I have killed Mobos with that as well as drive controllers.) With a seperated ATA bus for each drive you can achive hot plug capability which works quite well and saves you the trouble of powering down your server setup just to add a drive.

    Like the Xserve the RAID also has a seperate ATA/100 bus for each drive! That way the four drives in an Xserve can use the maximum bandwith of the 64bit/66MHz PCI bussystem that allows for peak 533MB/s transfer giving 266MB/s of real transfer speed. Since every PCI slot on the Xserve has it's own PCI bus and PCI controller you can use the full bandwidth and there's no tax for sharing the bus between several devices.

    Combining the throughput of several ATA100 drives you can actually transfer a theretical maximum of 266MB/s compared to 160MB/s on a SCSI bus. So there's more room to grow with drive mechanisms or more drives combined as used in the Xserve RAID.

    This combination makes up for the lower rpm compared to extreme high end SCSI devices. 15000 rpm is nice but still doesn't give the throughput a 3 or 4 channel ATA RAID can provide. At a fraction of the cost, heat and noise. 7200rpm drives also last longer than those cheethas, barracudas an whatever they are calle. Don't forget that servers usually are up 24/7 with the drives constantly revolving resulting in heavy wear and tear on the drives mechanics. (heads, bearings, motors, cooling, etc.) Not all drives (especially not high rpm ones) are specified to be run permanently. Check drive manufacturers spec sheets! Most of them are guranteed for 16 hours a day only. Not suitable for servers. Slower drives stay cooler and therefor last longer. Apple uses 7200rpm ATA drives for their modules, that's plenty of speed if you take more than a single drive. (After all that's the idea behind a RAID)

    Apple also makes use of SMART (Self-Monitoring, Analysis and Reporting Technology) in their drive modules. This is quite nice since it allows to tell if a drive is likely to die in the near future. A small processor on the controller and drive monitores some critical data like temperature of the bearings, rpm, power consumption and ergularly compares it to reference values. Should on of those exceed a certain tolerance SMART will alert you. (Say a drive bearing is worn. Therefor it gets hotter than it should but still works on for some time before it actually fails. SMART tells you that so you have a chance to change the drive before a disaster happens.) The small problem with SMART is that it only specifies a protocol to tell you the failure data. It does not specify WHAT the drive tells you only how to tell it. So you need to understand the drive's data. Server Monitor does understand this data told in the SMART language. Since different drive mechanisms have different specs, hence different failure values your software needs to know the drive it shall monitor! Therefor it's a bad idea to swap the mechanism in Apple's drive modules. I know the drive modules aren't the cheapes, but still a bargain compared to U160 drives. The modules also incorporate custom electronics and mechanics. Mechanics to lock the drive module and hold it in place. Custom electronics that tell your system that a drive will be removed as soon as you flide out the handle bar allowing for a clean unmount. The drive's status leds will tell you when the system has sucessfully and cleanly unmounted the volumes so you can remove the drive without risk of data loss.

    You might want to have a look at Apple's webpage on the <a href=""; target="_blank">Xserve</a> and it's <a href=""; target="_blank">architecture</a> .

    I'll try to get some more info on the Xserve RAID and it's internals beyond what I've already posted here.
  • Reply 17 of 28
    Man, after reading that, I sure wish I had 10k to burn. Heh. I can dream, I suppose.
  • Reply 18 of 28
    spiffsterspiffster Posts: 327member
    Wow, Monsterjeager, your knowledge is quite vast. I hate to has you another (probably stupid <img src="graemlins/embarrassed.gif" border="0" alt="[Embarrassed]" /> )) question, but?

    What is the difference between the different levels of RAID. Speed? Capacity? Thanks in advance, and for everything else you brought to this thread.
  • Reply 19 of 28
    If the xRaid is FibreChannel attached,

    and the internal disks are ATA-based, what

    is the encapsulation used over fibre-channel.

    Usually this is SCSI. This is what the EMC Clariion range uses, with direct fibre attached disk drives. Has someone developed a ATA layer

    for FibreChannel? or will there be some

    ATA-to-SCSI convertor hardware in the xRaid?

    Just some thoughts...

  • Reply 20 of 28
    My big question is...will apple release an xRAID that can be used for PowerMac TOWERS...not just for the xServe. Any speculation? I think that they would sell as many to Audio/Video/3D/Multimedia Pros for their towers as they do for the xServes if not more!! (assuming the price is right) With apple's recent intrest in video and 3D it only makes sense. waddya think?
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