Chris Hoefler
Dabbler
- Joined
- Dec 18, 2013
- Messages
- 22
Ok, so hardware, and especially SATA/SAS controllers has been discussed at length in various forum posts. For example, these recent posts about HBA vs. RAID cards,
http://forums.freenas.org/threads/confused-about-that-lsi-card-join-the-crowd.11901/
http://forums.freenas.org/threads/so-you-want-some-hardware-suggestions.12276/
Usually, when the Dell Perc controller is brought up, the recommendation is to throw it away and get some other controller. There are posts elsewhere that suggest that a Perc is at least usable (perhaps not ideal) with ZFS as long as you create RAID-0 volumes for each disk.
Rather than focus on recommended SAS/SATA cards, I would like to pose the simple question: Has anybody achieved a stable and reliable FreeNAS configuration with a Dell Perc card? Either Perc 5 or 6 with any version of FreeNAS, but especially 9.2.0.
The reason I ask is because I spent some time tracking down a very hard to diagnose problem that ended up being the Perc card. There was no obvious error message and no core dump. The card was recognized and supported by the mfi driver. The firmwares were up-to-date. The drives were accessible and working. The problem was that the system would spontaneously reboot. It seemed to happen when under a write load, primarily, but it also didn't seem to be a problem under certain benchmarks (ex: iozone). So, I still don't know what the problem was, whether it was the card or the driver or some magic aether dust, but I stopped getting spontaneous reboots as soon as I moved to a different controller.
An obvious question, why didn't I heed the advice to get an HBA card? Well, a few reasons,
This, in my opinion, is a bit different from hardware incompatibility. FreeBSD recognizes the card. It is supported. The drivers have been around for ages. This is a more subtle issue that may be specific to ZFS, or using two controllers at once. Whatever the actual issue, I would like to know if there was any reason to think the Perc was hopeless from the beginning. Because if that is case, I think it would be good to document somewhere.
http://forums.freenas.org/threads/confused-about-that-lsi-card-join-the-crowd.11901/
http://forums.freenas.org/threads/so-you-want-some-hardware-suggestions.12276/
Usually, when the Dell Perc controller is brought up, the recommendation is to throw it away and get some other controller. There are posts elsewhere that suggest that a Perc is at least usable (perhaps not ideal) with ZFS as long as you create RAID-0 volumes for each disk.
Rather than focus on recommended SAS/SATA cards, I would like to pose the simple question: Has anybody achieved a stable and reliable FreeNAS configuration with a Dell Perc card? Either Perc 5 or 6 with any version of FreeNAS, but especially 9.2.0.
The reason I ask is because I spent some time tracking down a very hard to diagnose problem that ended up being the Perc card. There was no obvious error message and no core dump. The card was recognized and supported by the mfi driver. The firmwares were up-to-date. The drives were accessible and working. The problem was that the system would spontaneously reboot. It seemed to happen when under a write load, primarily, but it also didn't seem to be a problem under certain benchmarks (ex: iozone). So, I still don't know what the problem was, whether it was the card or the driver or some magic aether dust, but I stopped getting spontaneous reboots as soon as I moved to a different controller.
An obvious question, why didn't I heed the advice to get an HBA card? Well, a few reasons,
- The concerns around the Perc seemed to center on the need to create RAID-0 problems, but not on reliability or stability issues. I had my main ZFS volume on a different card in an enclosure. I just needed the Perc for the drives that FreeNAS was going to be installed on, the ZIL, and the L2ARC, so I wasn't concerned about needing to create a handful of RAID-0 volumes.
- I was already buying a SAS HBA to drive the enclosure, did I really need to buy two?
- On my box the Perc is integrated, so I really would be throwing away otherwise perfectly usable silicon (by not being able to put it into a different box not running FreeNAS).
This, in my opinion, is a bit different from hardware incompatibility. FreeBSD recognizes the card. It is supported. The drivers have been around for ages. This is a more subtle issue that may be specific to ZFS, or using two controllers at once. Whatever the actual issue, I would like to know if there was any reason to think the Perc was hopeless from the beginning. Because if that is case, I think it would be good to document somewhere.