Problems with FreeNAS 8.0.1-beta4 + ZFS volumes in a RAID

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Jul 26, 2011

Originally I have posted this to the freenas-devel mailing list, but I think that here is more appropriate.

We have assembled a storage system with a Supermicro X8DTL-iF motherboard, a Supermicro SAS-846EL backplane and a SRCSASRB Intel RAID controller.
There are 5 SATA 2TB Seagate Constellation ES disks and 2 more 80GB SATA Samsung HD080HJ disks. Samsung disks are in RAID 1 and the Seagate in a RAID 5 configuration.
Diagram of slots and how the disks are being used is available at

Installing FreeNAS 8.0 RC5 on the RAID 1 disks and then creating a ZFS volume (now with FreeNAS already running) on the RAID 5 disks works without any problems.
Then, testing with 8.0.1-beta4 and doing the same steps (installing it to the RAID 1 and trying to create a ZFS volume on the RAID 5 disks), we receive a disk failure (right after the volume is created) on slot 5.

We have exchanged the RAID controller by a Intel RS2WG160 and we can reproduce the same problem.
Likewise, we have exchanged the disk at slot 5 with other disks (from the other slots) and it always fail on slot 5.

All the disks were tested in the current storage system and another different system using Linux; tests made were SMART's extended self-test routine + badblocks and they are all good.

We suspect that it's something related with FreeNAS and/or ZFS.
Why the disk at slot 5 always fail when creating a ZFS volume on newer FreeNAS while it's properly working with older releases and with Linux?
Can somebody give us some light, please?

Thank you!
May 27, 2011
i don't know how zfs or freenas could cause a disk to fail... the controller and it's error detection are abstracted away from zfs. zfs only sees a single block device.

can destroy your raid5 and just usethe bare drives in a zfs raidz(2) see what happens?


why are you using ZFS on a raid5 volume?, beats the purpose of ZFS :)
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