Date: Thu, 11 Apr 2013 13:25:12 +0400 (MSK) From: Dmitry Morozovsky <marck@rinet.ru> To: "Lawrence K. Chen, P.Eng." <lkchen@ksu.edu> Cc: freebsd-fs@freebsd.org Subject: Re: ZFS-inly server and dedicated ZIL Message-ID: <alpine.BSF.2.00.1304111320260.63303@woozle.rinet.ru> In-Reply-To: <802657359.5644092.1365629966726.JavaMail.root@k-state.edu> References: <802657359.5644092.1365629966726.JavaMail.root@k-state.edu>
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On Wed, 10 Apr 2013, Lawrence K. Chen, P.Eng. wrote: > The root pool only having one root vdev is probably a restriction on what functionality could be put into the bootblock. > > But, can't really tell what it is you're trying to do... > > You say raid10-like ZFS with two SSDs....which to me means you have at least 4 physical drives, and 2 SSDs. > > zpool create tank mirror disk1 disk2 mirror disk3 disk4 .... log ... cache .... > > perhaps as: .... log mirror ssd1a ssd2a cache ssd1b ssd2b Yes, exactly this way (gpt partitions, but nevermind). And before adding log I booted from this pool perfectly. > tank is load-balancing onto sets of mirrors, with a mirror of the first > partition of the two ssds for ZIL and using the second partition of the two > ssds concurrently for cache. > > So, in this case....tank can't be used as a root pool. an Internal USB stick > as your root pool would be one way to go. or you could carve out another > partition on the SSDs for a root pool. I'm now thinking of putting /boot on the first pair of disks to boot from, avoiding SPOF in this area too. > On my home system, I currently have a pair of SSDs....each with 7 > partitions.... 5 tiny ones for mirror ZILs for the other zpools in my system, > the mirrored root pool and partitions to be L2ARC for the two zpools in my > system that I'm using dedup in. (there's currently only 4 zpools in my > system, including the root....but I had originally envisioned the possibility > of adding additional external jbod arrays....) What is not clear for me is why one could want more than one pool in one machine? Thanks for your comments, will test further. > > I used to have 6 disk raid10-like with part of an external SSD for its zil...and no cache. It has since been redone as a raidz2 with mirrored zil (from the internal SSDs)....planning to add another SSD soon. > > ----- Original Message ----- > > Dear colleagues, > > > > I'm planning to make new PostgreSQL server using zaid10-like ZFS with > > two SSDs > > splitted into mirrored ZIL and striped arc2. However, it seems > > current > > ZFS implementation does not support this: > > > > ./lib/libzfs/common/libzfs_pool.c- case EDOM: > > ./lib/libzfs/common/libzfs_pool.c- zfs_error_aux(hdl, > > dgettext(TEXT_DOMAIN, > > ./lib/libzfs/common/libzfs_pool.c: "root pool can not have > > multiple vdevs" > > ./lib/libzfs/common/libzfs_pool.c- " or separate logs")); > > ./lib/libzfs/common/libzfs_pool.c- (void) zfs_error(hdl, > > EZFS_POOL_NOTSUP, msg); > > > > Am I right, or did I missed something obvious? > > > > Ok, if so: In this situation, I see two possibilities: > > - make system boot from internal USB stick (only /bootdisk with /boot > > and > > /rescue) with the rest of ZFS-on-root > > - use dedicated pair of disks for ZFS pool without ZIL for system. > > > > what would you recommend? > > > > Thanks! > > > > -- > > Sincerely, > > D.Marck [DM5020, MCK-RIPE, > > DM3-RIPN] > > [ FreeBSD committer: > > marck@FreeBSD.org ] > > ------------------------------------------------------------------------ > > *** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck@rinet.ru > > *** > _______________________________________________ > freebsd-fs@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-fs > To unsubscribe, send any mail to "freebsd-fs-unsubscribe@freebsd.org" > -- Sincerely, D.Marck [DM5020, MCK-RIPE, DM3-RIPN] [ FreeBSD committer: marck@FreeBSD.org ] ------------------------------------------------------------------------ *** Dmitry Morozovsky --- D.Marck --- Wild Woozle --- marck@rinet.ru *** ------------------------------------------------------------------------
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