Hello, On Mon, 26 Sep 2016 08:28:02 +0100 David wrote: > Ryan, a team at Ebay recently did some metadata testing, have a search on > this list. Pretty sure they found there wasn't a huge benefit it putting > the metadata pool on solid. As Christian says, it's all about ram and Cpu. > You want to get as many inodes into cache as possible. > This is the slide show / test in question, btw: http://www.slideshare.net/XiaoxiChen3/cephfs-jewel-mds-performance-benchmark > On 26 Sep 2016 2:09 a.m., "Christian Balzer" <chibi@xxxxxxx> wrote: > > > > > Hello, > > > > On Sun, 25 Sep 2016 19:51:25 -0400 (EDT) Tyler Bishop wrote: > > > > > 800TB of NVMe? That sounds wonderful! > > > > > That's not what he wrote at all. > > 800TB capacity, of which the meta-data will likely be a small fraction. > > > > As for the OP, try your google foo on the ML archives, this of course has > > been discussed before. > > See the "CephFS in the wild" thread 3 months ago for example. > > > > In short, you need to have an idea of the number of files and calculate > > 2KB per object (file). > > Plus some overhead for the underlying OSD FS, for the time being at least. > > > > And while having the meta-data pool on fast storage certainly won't hurt, > > the consensus here seems to be that the CPU (few, fast cores) and RAM of > > the MDS have a much higher priority/benefit. > > > > Christian > > > > > > ----- Original Message ----- > > > From: "Ryan Leimenstoll" <rleimens@xxxxxxxxxxxxxx> > > > To: "ceph new" <ceph-users@xxxxxxxxxxxxxx> > > > Sent: Saturday, September 24, 2016 5:37:08 PM > > > Subject: CephFS metadata pool size > > > > > > Hi all, > > > > > > We are in the process of expanding our current Ceph deployment (Jewel, > > 10.2.2) to incorporate CephFS for fast, network attached scratch storage. > > We are looking to have the metadata pool exist entirely on SSDs (or NVMe), > > however I am not sure how big to expect this pool to grow to. Is there any > > good rule of thumb or guidance to getting an estimate on this before > > purchasing hardware? We are expecting upwards of 800T usable capacity at > > the start. > > > > > > Thanks for any insight! > > > > > > Ryan Leimenstoll > > > rleimens@xxxxxxxxxxxxxx > > > University of Maryland Institute for Advanced Computer Studies > > > > > > _______________________________________________ > > > ceph-users mailing list > > > ceph-users@xxxxxxxxxxxxxx > > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > _______________________________________________ > > > ceph-users mailing list > > > ceph-users@xxxxxxxxxxxxxx > > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > > > > > > -- > > Christian Balzer Network/Systems Engineer > > chibi@xxxxxxx Global OnLine Japan/Rakuten Communications > > http://www.gol.com/ > > _______________________________________________ > > ceph-users mailing list > > ceph-users@xxxxxxxxxxxxxx > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > -- Christian Balzer Network/Systems Engineer chibi@xxxxxxx Global OnLine Japan/Rakuten Communications http://www.gol.com/ _______________________________________________ ceph-users mailing list ceph-users@xxxxxxxxxxxxxx http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com
 |