Hardware RAID or software for ZFS
bsd at todoo.biz
bsd at todoo.biz
Tue Nov 18 18:05:18 UTC 2014
> Le 18 nov. 2014 à 18:29, Matthew Seaman <matthew at freebsd.org> a écrit :
> On 11/18/14 15:28, bsd at todoo.biz wrote:
>> I would need your help in order to figure out which will be the best in order to setup a server which will be used as a Poudriere server.
>> My question is related to the usage of hardware RAID controller (JBOD) or software based controller (graid)
>> Server we are targeting is a SuperMicro 1018R-WC0R - 1U
>> I used to build my server using an HBA such as LSI SAS 9207-8i or LSI SAS 9201-16i
>> Then I’ll configure the HBA as JBOD so that disks can be presented correctly to the system so that we can build our ZFS FS on top of that.
>> My sysadmin suggested me to get rid of the HBA and use direct connectivity and Graid.
>> I would like to have some feedback on various aspects :
>> 1. performance
>> 2. usability
>> 3. problem one might have encountered
> OK -- Your sysadmin is correct about the direct connectivity thing, but
> graid? Seriously? That's an option for really cheap and some might say
> quite nasty pseudo-raid things you get on some desktop hardware. If
> you're going to be building a significant number of packages with any
> regularity, then you're going to need something better than that.
> The LSI HBAs you suggest are known to work well with FreeBSD. If you're
> going to be using ZFS -- which is really a no-brainer for a poudriere
> box, as poudriere has a lot of functionality built around cloning and
> snapshotting and other things that come naturally to ZFS[*] -- well, in
> that case, ideally you want ZFS to have direct access to the disk devices.
> With LSI, when they say 'JBOD' this direct access is generally what they
> mean -- although depending on the precise model you get, you may need to
> flash the device with different firmware to get the characteristics you
> want. Some other RAID controller manufacturers essentially give you a
> load of single-disk RAID-0 devices, so there's still a layer of RAID
> controller stuff between ZFS and the disk. That isn't the kiss of death
> to the idea of building a zpool from it, but it's less optimal.
> On the three aspecs you mention:
> performance depends very much on the precise type of disk hardware
> you specify, how you configure the zpool (for instance, will you be
> using ZIL or ARC devices?) and on having enough RAM in the system to
> provide an effective buffer-cache for all those ZFS filesystems.
> usability. I'd say ZFS is pretty usable. Once it's set up, you
> don't really need to interact with things at the level of the HBA. It
> just works.
> problems: this depends very much on the details of what you're trying
> to do. But IMHO you're on the right track with what you've described so
> [*] Although poudriere does now work on UFS as well and has done for a
> year or so.
Thank you very much for this documented and precise answer.
I think that the hardware we were targeting is a bit too new and is not yet marked as « ok » for FreeBSD by SuperMicro.
We will probably go for a little bit older hardware that’s 100% known to work ok with FreeBSD.
I have already been building quite large NAS using this setup (JBOD Controller + ZFS on top) and I had very interesting perfs.
I didn’t know about the problem with native JBOD and controller SW update/upgrade…
> SuperMicro 1018R-WC0R - 1U
This is the one we wanted to target but It doesn’t seem to be on the hardware list marked as FreeBSD compatible.
Thanks all - long leave FBSD.
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