8 Replies Latest reply: Apr 9, 2010 8:15 PM by jgsenecal
jgsenecal Level 1 Level 1 (0 points)
Hi all,

What are the real issues when using non-Apple RAID hardware and XSAN?

We need to add some additional capacity to our SAN, and I've been tasked with pricing. As currently configured, it's 100% Apple hardware (except the switches, of course). We'd like to keep it that way, but we're at a critical point where money is extremely tight (Congress hasn't approved a budget, and layoffs are coming in January). We may have to install some non-Apple products as a cost-saving measure.

I received a quote for Xserve RAIDs from our contracted supplier and Apple Sales Rep, but the quote, while cheaper than what I could do on the Apple store, is significantly more expensive that competing products that are more modern. For several $k less I can get a comparable product with SATA-II, 4Gbit fibre, RAID-6, and a larger drive capacity (16 instead of 14). For the same price I can get all this plus a product that's more reliable (redundant controllers and fibre ports).

The Apple Sales Rep is of course trying to sell me on Apple quality, interoperability, drive reliability, etc. I'm reluctant to purchase hardware that uses technology that's on its way out. Currently, the only advantage I see to the Apple product is the interface. It is very easy to set up and use. But the competing products aren't that bad. As I understand it, XSAN only wants a block-addressable device and communicates with it via fibre--there's no communication with storage via Ethernet.

So I ask: what are the real issues when using non-Apple storage with XSAN? Anyone operating a heterogeneous XSAN? Is it reliable enough? Were there serious problems (if so, what?)? Any non-Apple products that XSAN likes more than others?

Any practical information or advice that you can offer would be greatly appreciated.

To address some things preemptively:

* Our SAN is old enough so that any multi-year Apple support agreement has already expired.
* Regarding the quality of Apple (Hitachi) drives, drive burn-in can be done ourselves (the utilities exist), and the Google paper indicates that there's no real advantage to using enterprise-class drives.

Thanks very much!

-Josh

PowerMac G4 "Sawtooth", Mac OS X (10.4.11), Upgraded to 1 GHz, Radeon 9200
  • 1. Re: Non-Apple RAID hardware and XSAN--What are the real issues?
    Robert Gassler Level 1 Level 1 (30 points)
    I have struggled with the same problem and i have tried 2 solutions:

    1. third part RAID units (in my case easyraidQ16): this worked really well, and you can make LUNs of any size. It seems a tiny bit slower but that is most probably due to Raid6. And the configuration interface is pretty bad, but it can be used.

    2. Replace the Apple drives in the Xserve Raids with standard ATA drives of higher capacity (you can only go up to 750GB). Again, i didn't encounter any problems. One of the ATA drives failed after a few weeks, but i could do a warranty exchange with the manufacturer. Since then, no problems at all. Everything is working fine.

    My advice would be to go for solution 2, until Apple comes out with more modern hardware (provided you have a 100% backup as you will need to rebuild your SAN).

    hope this helps,
    robert
  • 2. Re: Non-Apple RAID hardware and XSAN--What are the real issues?
    jgsenecal Level 1 Level 1 (0 points)
    Hi Robert,

    Thanks for taking the time to respond.

    2. Replace the Apple drives in the Xserve Raids with standard ATA drives of higher capacity (you can only go up to 750GB). Again, i didn't encounter any problems. One of the ATA drives failed after a few weeks, but i could do a warranty exchange with the manufacturer. Since then, no problems at all. Everything is working fine.


    Upgrading some of our 400GB disk-based storage to 750 would see us through for a while, but it would be a larger headache than I want to deal with at this point--I don't have time to rebuild the SAN. Plus, the Apple 750 modules are expensive.

    As an aside, according to a contact at Apple (an associate of our sales rep) there is a way to upgrade storage hardware that's part of an XSAN without rebuilding the whole thing. Details were promised but have not been provided yet.

    1. third part RAID units (in my case easyraidQ16): this worked really well, and you can make LUNs of any size. It seems a tiny bit slower but that is most probably due to Raid6. And the configuration interface is pretty bad, but it can be used.


    Our storage needs are such that we may have to install third-party storage just to get the amount of space we will likely require (we chewed through 14 TB in three weeks recently). I'm glad to hear you didn't have any problems with XSAN and third-party hardware--that's promising.

    -Josh
  • 3. Re: Non-Apple RAID hardware and XSAN--What are the real issues?
    Robert Gassler Level 1 Level 1 (30 points)
    Dear josh,

    i didn't mean to replace 400GB modules with 750GB apple module, i simply swapped the disk in the modules with standard 750GB drives (very cheap).

    you are right, there is a way of swapping out disks without rebuilding the SAN, but it is complicated. You need to first: re-allocate all files that have parts stored in the Raid that you replace
    then, change the config files of the SAN volume (set the replaced Raids to DOWN)
    then add the newly configured RAIDs

    robert
  • 4. Re: Non-Apple RAID hardware and XSAN--What are the real issues?
    jgsenecal Level 1 Level 1 (0 points)
    Is this process documented anywhere?

    -Josh
  • 5. Re: Non-Apple RAID hardware and XSAN--What are the real issues?
    Robert Gassler Level 1 Level 1 (30 points)
    I do not think it is documented anywhere. My IT guys have written 2 scripts to support this:

    1. a script to set the allocation of all folders and subfolders to a specific storage pool
    2. a script to re-allocate all files with extents in a specific storage pool to another storage pool

    the editing of the config files is rather easy. i could write up a short document on how to do this.

    i can send you the scripts but i cannot not really supply extensive tech support for this.

    robert
  • 6. Re: Non-Apple RAID hardware and XSAN--What are the real issues?
    Donald Kok Level 2 Level 2 (490 points)
    I would like to read these details on the xsanity wiki at http://wiki.xsanity.com/groups/xsanitywiki
    Thanks!
  • 7. Re: Non-Apple RAID hardware and XSAN--What are the real issues?
    jgsenecal Level 1 Level 1 (0 points)

    the editing of the config files is rather easy. i could write up a short document on how to do this.


    If you could, I'd appreciate it. No rush--this isn't something we'd be doing for a while.

    i can send you the scripts but i cannot not really supply extensive tech support for this.


    Understood--I'm not expecting any.

    Thanks!

    -Josh
  • 8. Re: Non-Apple RAID hardware and XSAN--What are the real issues?
    jgsenecal Level 1 Level 1 (0 points)
    We installed Non-Apple higher-density drives, and everything was fine.