Stu, Is there a reason why you picked Raidz 3 rather than 4 way mirror across 4 disks? Raidz 3 parity calculation might take more cpu resources rather than mirroring across disks but also the latency may be higher in mirroring to sync across all the disks. Wondering if you did some testing before deciding it.
On Fri, Jul 21, 2017 at 12:27 AM Stu Midgley <sdm...@gmail.com> wrote: > we have been happily using 2.9.52+0.7.0-rc3 for a while now. > > The MDT is a raidz3 across 4 disks. > > On Fri, Jul 21, 2017 at 1:19 PM, Isaac Huang <he.hu...@intel.com> wrote: > >> On Fri, Jul 21, 2017 at 12:54:15PM +0800, Stu Midgley wrote: >> > Afternoon >> > >> > I have an MDS running on spinning media and wish to migrate it to SSD's. >> > >> > Lustre 2.9.52 >> > ZFS 0.7.0-rc3 >> >> This may not be a stable combination - I don't think Lustre officially >> supports 0.7.0-rc yet. Plus, there's a recent Lustre osd-zfs bug and >> its fix hasn't been back ported to 2.9 yet (to the best of my knowledge): >> https://jira.hpdd.intel.com/browse/LU-9305 >> >> > How do I do it? >> >> Depends on how you've configured the MDT pool. If the disks are >> mirrored or just plan disks without any redundancy (i.e. not RAIDz), >> you can simply attach the SSDs to the hard drives to form or extend >> mirrors and then detach the hard drives - see zpool attach/detach. >> >> -Isaac >> > > > > -- > Dr Stuart Midgley > sdm...@gmail.com > _______________________________________________ > lustre-discuss mailing list > lustre-discuss@lists.lustre.org > http://lists.lustre.org/listinfo.cgi/lustre-discuss-lustre.org >
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