<div dir="ltr"><br><div>I've had good results with using SSD as LVM cache for gluster bricks (<a href="http://man7.org/linux/man-pages/man7/lvmcache.7.html">http://man7.org/linux/man-pages/man7/lvmcache.7.html</a>). I still use XFS on bricks.</div><div><br></div><div><br></div></div><div class="gmail_extra"><br><div class="gmail_quote">On Tue, Oct 10, 2017 at 12:27 PM, Jeff Darcy <span dir="ltr"><<a href="mailto:jeff@pl.atyp.us" target="_blank">jeff@pl.atyp.us</a>></span> wrote:<br><blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">On Tue, Oct 10, 2017, at 11:19 AM, Gandalf Corvotempesta wrote:<br>
> Anyone made some performance comparison between XFS and ZFS with ZIL<br>
> on SSD, in gluster environment ?<br>
><br>
> I've tried to compare both on another SDS (LizardFS) and I haven't<br>
> seen any tangible performance improvement.<br>
><br>
> Is gluster different ?<br>
<br>
Probably not. If there is, it would probably favor XFS. The developers<br>
at Red Hat use XFS almost exclusively. We at Facebook have a mix, but<br>
XFS is (I think) the most common. Whatever the developers use tends to<br>
become "the way local filesystems work" and code is written based on<br>
that profile, so even without intention that tends to get a bit of a<br>
boost. To the extent that ZFS makes different tradeoffs - e.g. using<br>
lots more memory, very different disk access patterns - it's probably<br>
going to have a bit more of an "impedance mismatch" with the choices<br>
Gluster itself has made.<br>
<br>
If you're interested in ways to benefit from a disk+SSD combo under XFS,<br>
it is possible to configure XFS with a separate journal device but I<br>
believe there were some bugs encountered when doing that. Richard<br>
Wareing's upcoming Dev Summit talk on Hybrid XFS might cover those, in<br>
addition to his own work on using an SSD in even more interesting ways.<br>
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</blockquote></div><br></div>