Hi Richard, So do you rely on the CEPH to automatically decide the WAL device's location and size?
On Thu, Nov 23, 2017 at 4:04 PM, Richard Hesketh < [email protected]> wrote: > Keep in mind that as yet we don't really have good estimates for how large > bluestore metadata DBs may become, but it will be somewhat proportional to > your number of objects. Considering the size of your OSDs, a 15GB block.db > partition is almost certainly too small. Unless you've got a compelling > reason not to you should probably partition your SSDs to use all the > available space. Personally, I manually partition my block.db devices into > even partitions and then invoke creation with > > ceph-disk prepare --bluestore /dev/sdX --block.db /dev/disk/by-partuuid/ > whateveritis > > Invoking by UUID is done because if presented an existing partition rather > than the root block device it will just symlink precisely to the argument > given, so using /dev/sdXYZ arguments is dangerous as they may not be > consistent across hardware changes or even just reboots depending on your > system. > > Rich > > On 23/11/17 09:53, Caspar Smit wrote: > > Rudi, > > > > First off all do not deploy an OSD specifying the same seperate device > for DB and WAL: > > > > Please read the following why: > > > > http://docs.ceph.com/docs/master/rados/configuration/ > bluestore-config-ref/ > > > > > > That said you have a fairly large amount of SSD size available so i > recommend using it as block.db: > > > > You can specify a fixed size block.db size in ceph.conf using: > > > > [global] > > bluestore_block_db_size = 16106127360 > > > > The above is a 15GB block.db size > > > > Now when you deploy an OSD with a seperate block.db device the partition > will be 15GB. > > > > The default size is a percentage of the device i believe and not always > a usable amount. > > > > Caspar > > > > Met vriendelijke groet, > > > > Caspar Smit > > Systemengineer > > SuperNAS > > Dorsvlegelstraat 13 > > 1445 PA Purmerend > > > > t: (+31) 299 410 414 > > e: [email protected] <mailto:[email protected]> > > w: www.supernas.eu <http://www.supernas.eu> > > > > 2017-11-23 10:27 GMT+01:00 Rudi Ahlers <[email protected] <mailto: > [email protected]>>: > > > > Hi, > > > > Can someone please explain this to me in layman's terms. How big a > WAL drive do I really need? > > > > I have a 2x 400GB SSD drives used as WAL / DB drive and 4x 8TB HDD's > used as OSD's. When I look at the drive partitions the DB / WAL partitions > are only 576Mb & 1GB respectively. This feels a bit small. > > > > > > root@virt1:~# lsblk > > NAME MAJ:MIN RM SIZE RO TYPE MOUNTPOINT > > sda 8:0 0 7.3T 0 disk > > ├─sda1 8:1 0 100M 0 part /var/lib/ceph/osd/ceph-0 > > └─sda2 8:2 0 7.3T 0 part > > sdb 8:16 0 7.3T 0 disk > > ├─sdb1 8:17 0 100M 0 part /var/lib/ceph/osd/ceph-1 > > └─sdb2 8:18 0 7.3T 0 part > > sdc 8:32 0 7.3T 0 disk > > ├─sdc1 8:33 0 100M 0 part /var/lib/ceph/osd/ceph-2 > > └─sdc2 8:34 0 7.3T 0 part > > sdd 8:48 0 7.3T 0 disk > > ├─sdd1 8:49 0 100M 0 part /var/lib/ceph/osd/ceph-3 > > └─sdd2 8:50 0 7.3T 0 part > > sde 8:64 0 372.6G 0 disk > > ├─sde1 8:65 0 1G 0 part > > ├─sde2 8:66 0 576M 0 part > > ├─sde3 8:67 0 1G 0 part > > └─sde4 8:68 0 576M 0 part > > sdf 8:80 0 372.6G 0 disk > > ├─sdf1 8:81 0 1G 0 part > > ├─sdf2 8:82 0 576M 0 part > > ├─sdf3 8:83 0 1G 0 part > > └─sdf4 8:84 0 576M 0 part > > sdg 8:96 0 118G 0 disk > > ├─sdg1 8:97 0 1M 0 part > > ├─sdg2 8:98 0 256M 0 part /boot/efi > > └─sdg3 8:99 0 117.8G 0 part > > ├─pve-swap 253:0 0 8G 0 lvm [SWAP] > > ├─pve-root 253:1 0 29.3G 0 lvm / > > ├─pve-data_tmeta 253:2 0 68M 0 lvm > > │ └─pve-data 253:4 0 65.9G 0 lvm > > └─pve-data_tdata 253:3 0 65.9G 0 lvm > > └─pve-data 253:4 0 65.9G 0 lvm > > > > > > > > > > -- > > Kind Regards > > Rudi Ahlers > > Website: http://www.rudiahlers.co.za > > > > _______________________________________________ > > ceph-users mailing list > > [email protected] <mailto:[email protected]> > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com < > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com> > > > > > > > > > > _______________________________________________ > > ceph-users mailing list > > [email protected] > > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > > > > -- > Richard Hesketh > Systems Engineer, Research Platforms > BBC Research & Development > > > _______________________________________________ > ceph-users mailing list > [email protected] > http://lists.ceph.com/listinfo.cgi/ceph-users-ceph.com > > -- Kind Regards Rudi Ahlers Website: http://www.rudiahlers.co.za
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