> -----Original Message----- > From: linux-btrfs-owner@xxxxxxxxxxxxxxx <linux-btrfs- > owner@xxxxxxxxxxxxxxx> On Behalf Of Andrei Borzenkov > Sent: Monday, 30 March 2020 4:46 PM > To: Victor Hooi <victorhooi@xxxxxxxxx>; linux-btrfs <linux- > btrfs@xxxxxxxxxxxxxxx> > Subject: Re: Using Intel Optane to accelerate a BTRFS array? (equivalent of > ZLOG/SIL for ZFS?) > > 30.03.2020 01:30, Victor Hooi пишет: > > Hi, > > > > I have a small 12-bay SuperMicro server I'm using as a local NAS, with > > FreeNAS/ZFS. > > > > Each drive is a 12TB HDD. > > > > I'm in the process of moving it to Linux - and I thought this might be > > a good chance to try out BTRFS again =). > > > > (I'd previously tried BTRFS many years a go, and hit some issues - > > it's possible this may have been made worse by my inexperience with > > BTRFS at the time - e.g. > > https://www.spinics.net/lists/linux-btrfs/msg04240.html) > > > > Anyhow - currently the server has a 750GB Intel Optane drive, that > > we're using as a ZLOG/SIL drive: > > > > Do you mean ZIL/SLOG? ZIL == ZFS Intent Log, SLOG == SSD Log. > > > https://www.ixsystems.com/community/threads/how-best-to-use-960gb- > opta > > ne-in-freenas-build.75798/#post-527264 > > > > My question is - what's the equivalent in BTRFS-land? > > > > Not on btrfs level. I guess using bcache on top of btrfs may achieve some > similar effects. > > > Or what is the best way to use an ultra-fast Intel Optane drive to > > accelerate reads/writes on a BTRFS array? > > > > > ZIL is *write* intent log, it does not directly accelerates reads. ZFS supports > SSD as second-level read cache, but as far as I remember it is physically > separate from ZIL. I have used caching with lvm under btrfs. It's a pain to setup correctly for a btrfs raid1 setup (need separate volume groups with separate logical volumes to ensure it's impossible to have two raid1 stripes on the same physical disk without noticing it) but it did work quite well and I never had any strange problems with it. Paul.
