5 Jul
2020
5 Jul
'20
4:56 a.m.
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)?
Conversely, what happens with the block.db if I place the wal with
--block.wal
Or do I have to setup separate partitions for the block.db and wal?
--
Lindsay
5 Jul
5 Jul
12:38 p.m.
On Sun, Jul 5, 2020 at 6:57 AM Lindsay Mathieson
<lindsay.mathieson(a)gmail.com> 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
1:16 p.m.
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.
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...
Conversely, what happens with the block.db if I
place the wal with
--block.wal
The db then stays with the data.
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
1398
days inactive
1398
days old
3 comments
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Alexander E. Patrakov -
Lindsay Mathieson