[ceph-users] Re: Placement of block/db and WAL on SSD?
On 5/07/2020 8:16 pm, Lindsay Mathieson wrote: But from what you are saying, the 500GB disk would have been gaining no benefit? I would be better off allocating 30GB (or 30GB) for each disk? Edit: 30GB or 62GB (its a 127GB SSD) -- Lindsay ___ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
[ceph-users] Re: Placement of block/db and WAL on SSD?
On 5/07/2020 7:38 pm, Alexander E. Patrakov wrote: If the wal location is not explicitly specified, it goes together with the db. So it is on the SSD. Conversely, what happens with the block.db if I place the wal with --block.wal The db then stays with the data. Ah, so my 2nd reading was correct. I've recreated the OSD's on this node 3 times now :) 1. HDD Only 2. HDD + WAL on SSD 3. HDD + DB/WAL on SSD However give the following, I see try 4 approaching... The partition needs to be 30 or 300 GB in size (this requirement was relaxed only very recently, so let's not count on this), but not smaller than 1-4% of the data device. Was not aware of that. I have two mismatched disk (500GB & 3TB) and was allocating space proportionally. * 25GB for the 500GB Disk * 100GB for the 3TB Disk But from what you are saying, the 500GB disk would have been gaining no benefit? I would be better off allocating 30GB (or 30GB) for each disk? * 1% for the 3TB (2.7TB effective) - RBD for VM's only. this requirement was relaxed only very recently, so let's not count on this Only in master and the size can be proportional to disk size now? Thanks! -- Lindsay ___ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
[ceph-users] Re: Placement of block/db and WAL on SSD?
On Sun, Jul 5, 2020 at 6:57 AM Lindsay Mathieson wrote: > > Nautilus install. > > Documentation seems a bit ambiguous to me - this is for a spinner + SSD, > using ceph-volume > > If I put the block.db on the SSD with > > "ceph-volume lvm create --bluestore --data /dev/sdd --block.db > /dev/sdc1" > > does the wal exists on the ssd (/dev/sdc1) as well, or does it remain on > the hdd (/dev/sdd)? If the wal location is not explicitly specified, it goes together with the db. So it is on the SSD. > > > Conversely, what happens with the block.db if I place the wal with > --block.wal The db then stays with the data. > Or do I have to setup separate partitions for the block.db and wal? You can, in theory, provide all three devices, but nobody does that in practice. Common setups are: 1) just --data, then the db and its wal are located on the same device; 2) --data on HDD and --block.db on a partition on the SSD (the wal automatically goes together with the db). The partition needs to be 30 or 300 GB in size (this requirement was relaxed only very recently, so let's not count on this), but not smaller than 1-4% of the data device. 3) --data on something (then the db goes there as well) and --block.wal on a small (i.e. not large enough to use as a db device) but very fast nvdimm. -- Alexander E. Patrakov CV: http://pc.cd/PLz7 ___ ceph-users mailing list -- ceph-users@ceph.io To unsubscribe send an email to ceph-users-le...@ceph.io
