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Given:

  1. One or more available Dell PowerEdge 2950 servers
  2. The desire to deploy ZFS iSCSI storage using Nexenta or Solaris
  3. ZFS uses software RAID
  4. Dell's PERC 5 RAID controllers do not support JBOD
  5. Presenting single-disk RAID 0 arrays in lieu of JBOD is not desirable

Question:

  1. I would like to replace the PERC with a SAS controller that is supported by Solaris and/or Nexenta. Do you have any personal recommendations?
  2. Would this be compatible with the existing backplane?
  3. What about external (MD1000) enclosures?
  4. Have you ever actually tried to do this with a Dell server? Do you have any other thoughts, recommendations, or bits of wisdom from personal experience?
Skyhawk
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  • Does anyone have personal experience running Solaris or Nexenta (non-virtualized) on common Dell hardware? Good, bad, ugly? – Skyhawk Oct 19 '10 at 14:21
  • How many disks of what type are you intending to use? – Chopper3 Oct 19 '10 at 19:09
  • Not nailed down. We probably would start with between six and eight 7200rpm 2TB drives (raidz2) plus SSDs for L2ARC and ZIL. – Skyhawk Oct 20 '10 at 23:29
  • I have the same setup and situation, and I am wondering why is it undesirable to present all the disks as single-disk-Raid-0 arrays? – Peter Valadez Feb 25 '12 at 02:01
  • It's undesirable because ZFS/Nexenta won't be able to rescan the RAID0 array/drive in the event of a failure/replacement. It forces you to have to reboot in order to recognize a new drive. Using multiple RAID0 drives configured through a non-HBA basically kills hot-swap functionality. Use on the controllers listed at: http://serverfault.com/questions/84043/zfs-sas-sata-controller-recommendations – ewwhite Feb 25 '12 at 02:09
  • Thanks a lot! I hadn't thought of that but it makes a lot of sense. If a drive dies, then the single-disk-Raid0 array will be failed and the only way to fix a failed array is to replace it through the Raid configuration utility in the BIOS. I haven't been able to install the LSI MegaRaid Utility on Nexentastor, but I supposed if you were able to install it you would be able to create a new array to replace the failed one. – Peter Valadez Feb 28 '12 at 01:58

4 Answers4

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In my experience, for ZFS LSI non-raid cards are the best. I use a Dell SAS6i (LSI 1068E rebadge) for internal drives and LSI SAS3801E (dual 3gbps 4x miniSAS ports) for external drives (MD1000) under Solaris 10 (s10u9) for ZFS at work, while I use the LSI SAS 9200-16e (quad 6gbps 4x miniSAS) at home with Nexenta (NCP3). Nothing but good things to say about LSI cards and support.

notpeter
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  • Fantastic. Just out of curiosity, what model is the server with the SAS/6i? – Skyhawk Nov 04 '10 at 03:49
  • I ran my Dell SAS6i/R in a 1950 III (testing) and then in a 2950 III (6mo production) but settled on a Sun x4250 (LSI 1068E too) with its SSD friendly 16x2.5inch backplane since my 1950/2950 have the 3.5inch backplanes. If you dont have a 8x2.5 backplaned 2950, you can mount SSDs in a free PCI slot (or just hanging out), use a Y-Cable for power from the DVD and attach to one of the internal SATA ports. – notpeter Nov 04 '10 at 23:09
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We use the LSI 1068 chipset HBA's such as LSI SAS 3081E-R with OpenSolaris. You can also find that chipset OEM'd by Intel and SuperMicro.

We use these internally on our ASUS boxes w/o a backplane. It should work on a backplane, but we just have that feature.

tegbains
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3

Dell's SAS 6/ir 'budget raid' adapters do JBOD unless the drive is in a RAID array. The cards work relatively well from my experience although I cannot attest to whether they work with Nexenta or Solaris.

See also this answer

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simplydave
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  • +1, looks like this also uses the LSI 1068 chipset *and* is compatible with the 2950 backplane. Much appreciated! – Skyhawk Oct 27 '10 at 02:22
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Isn't there an option to set SCSI mode instead of RAID mode in the PE2950 BIOS? If so, that should do the trick for you.

joeqwerty
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  • So far as I know, this is supported only on old SCSI models (PERC 4) and not SAS models (PERC 5/6), but I will double-check. – Skyhawk Oct 11 '10 at 18:12
  • OK. Also, I believe there's an option to disable the SATA and\or SAS controllers, so maybe that's the key. I haven't tried it for myself and presumably these servers are pre-production so monkeying around with the settings shouldn't do any harm. – joeqwerty Oct 11 '10 at 18:17