Given that I have lots of ProLiant equipment, are there any recommended controllers that would work in this situation? Is this an issue unique to the Smart Array controllers? If I do choose to use some level of hardware RAID on the existing Smart Array P400, what's the best way to use it with ZFS (assume 8 disks with an emphasis on capacity)?
-- Edmund William White ewwh...@mac.com > From: Craig Morgan <craig.mor...@sun.com> > Date: Tue, 27 Jan 2009 13:54:46 +0000 > To: Edmund White <ewwh...@mac.com> > Cc: Alex <a...@pancentric.com>, <zfs-discuss@opensolaris.org> > Subject: Re: [zfs-discuss] Problems using ZFS on Smart Array P400 > > You need to step back and appreciate that the manner in which you are > presenting Solaris with disks is the problem and not necessarily ZFS. > > As your storage system is incapable of JBOD operation, you have > decided to present each disk as a 'simple' RAID0 volume. Whilst this > looks like a 'pass-thru' access method to the disk and its contents, > it is far from it. The HW RAID sub-system is creating a logical volume > based on this single spindle (in exactly the same way it would be for > multiple spindles, aka a stripe), metadata is recorded by the RAID > system with regard to the make-up of said volume. > > The important issue here is that you have a non-redundant RAID (!) > config, hence a single failure (in this case your single spindle > failure) causes the RAID sub-system to declare the volume (and hence > its operational status) as failed, this in turn is declared to the OS > as a failed volume. At this juncture, intervention is normally > necessary to re-destroy/re-create a volume (remember no redundancy--- > so this is manual!) and hence re-present it to the OS (which will find > a new UID for the volume and treat it as a new device). On occasions > it may be possible to intervene and "resurrect" a volume by manually > overriding the status of the RAID0 volume, but in many HW RAID systems > this is not to be recommended. > > In short, you've got more abstractions (layers) in place than you need/ > desire and that is fundamentally the cause of your problem ... either > plump for a simpler array or swallow some loss of transparency in the > ZFS layer and present redundant RAID sets from your array, but live > with the consequences of increased admin and complexity and some loss > of transparency/protection---but hopefully the RAID sub-system will be > capable of automated recovery in most circumstances of simple failures. > > Craig > > On 27 Jan 2009, at 13:00, Edmund White wrote: > > > -- > Craig > > Craig Morgan > t: +44 (0)791 338 3190 > f: +44 (0)870 705 1726 > e: craig.mor...@sun.com > > ~ > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > NOTICE: This email message is for the sole use of the intended > recipient(s) and may contain confidential and privileged information. > Any unauthorized review, use, disclosure or distribution is > prohibited. > If you are not the intended recipient, please contact the sender by > reply email and destroy all copies of the original message. > ~ > ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ > > _______________________________________________ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
