2016-07-12 15:03 GMT+02:00 Vincent Godin <vince.ml...@gmail.com>: > Hello. > > I've been testing Intel 3500 as journal store for few HDD-based OSD. I > stumble on issues with multiple partitions (>4) and UDEV (sda5, sda6,etc > sometime do not appear after partition creation). And I'm thinking that > partition is not that useful for OSD management, because linux do no > allow partition rereading with it contains used volumes. > On my side if i launch "partprobe" after creating with fdisk on a disk which has mounted partitions, then it works
> > So my question: How you store many journals on SSD? My initial thoughts: > > 1) filesystem with filebased journals > 2) LVM with volumes > > Anything else? Best practice? > > P.S. I've done benchmarking: 3500 can support up to 16 10k-RPM HDD. > > Hello, > > I would like to advertise you not using 1 SSD for 16 HDD. Ceph journal is > not only a journal but a write cache during operation. I had that kind of > configuration with 1 SSD for 20 SATA HDD. With a Ceph bench, i notice that > my rate whas limited between 350 and 400 MB/s. In fact, a iostat show me > that my SSD was 100% utilised with a rate of 350-400 MB/s. > > If you consider that a SATA HDD can have a max average rate of 100 MB/s, > you need to configure one SSD (which can rate till 400 MB/s) for 4 SATA HDD > > Vincent > > _______________________________________________ > ceph-users mailing list > ceph-users@lists.ceph.com > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > -- *Guillaume Comte* 06 25 85 02 02 | guillaume.co...@blade-group.com <guilla...@blade-group.com> 90 avenue des Ternes, 75 017 Paris
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