Shouldn't Steven see some data being written to the block/wal for object
metadata? Though that might be negligible with 4MB objects
On 27-04-18 16:04, Serkan Çoban wrote:
rados bench is using 4MB block size for io. Try with with io size 4KB,
you will see ssd will be used for write operations.
On Fri, Apr 27, 2018 at 4:54 PM, Steven Vacaroaia <stef97@xxxxxxxxx> wrote:
Hi
During rados bench tests, I noticed that HDD usage goes to 100% but SSD
stays at ( or very close to 0)
Since I created OSD with BLOCK/WAL on SSD, shouldnt I see some "activity'
on SSD ?
How can I be sure CEPH is actually using SSD for WAL /DB ?
Note
I only have 2 HDD and one SSD per server for now
Comands used
rados bench -p rbd 50 write -t 32 --no-cleanup && rados bench -p rbd -t 32
50 rand
/usr/sbin/ceph-volume --cluster ceph lvm create --bluestore --data /dev/sdc
--block.wal /dev/disk/by-partuuid/32ffde6f-7249-40b9-9bc5-2b70f0c3f7ad
--block.db /dev/disk/by-partuuid/2d9ab913-7553-46fc-8f96-5ffee028098a
( partitions are on SSD ...see below)
sgdisk -p /dev/sda
Disk /dev/sda: 780140544 sectors, 372.0 GiB
Logical sector size: 512 bytes
Disk identifier (GUID): 5FE0EA74-7E65-45B8-A356-62240333491E
Partition table holds up to 128 entries
First usable sector is 34, last usable sector is 780140510
Partitions will be aligned on 2048-sector boundaries
Total free space is 520093629 sectors (248.0 GiB)
Number Start (sector) End (sector) Size Code Name
1 251660288 253757439 1024.0 MiB FFFF ceph WAL
2 2048 62916607 30.0 GiB FFFF ceph DB
3 253757440 255854591 1024.0 MiB FFFF ceph WAL
4 62916608 125831167 30.0 GiB FFFF ceph DB
5 255854592 257951743 1024.0 MiB FFFF ceph WAL
6 125831168 188745727 30.0 GiB FFFF ceph DB
7 257951744 260048895 1024.0 MiB FFFF ceph WAL
8 188745728 251660287 30.0 GiB FFFF ceph DB
[root@osd04 ~]# ls -al /dev/disk/by-partuuid/
total 0
drwxr-xr-x 2 root root 200 Apr 26 15:39 .
drwxr-xr-x 8 root root 160 Apr 27 08:45 ..
lrwxrwxrwx 1 root root 10 Apr 27 09:38 0baf986d-f786-4c1a-8962-834743b33e3a
-> ../../sda8
lrwxrwxrwx 1 root root 10 Apr 27 09:38 2d9ab913-7553-46fc-8f96-5ffee028098a
-> ../../sda2
lrwxrwxrwx 1 root root 10 Apr 27 09:38 32ffde6f-7249-40b9-9bc5-2b70f0c3f7ad
-> ../../sda3
lrwxrwxrwx 1 root root 10 Apr 27 09:38 3f4e2d47-d553-4809-9d4e-06ba37b4c384
-> ../../sda6
lrwxrwxrwx 1 root root 10 Apr 27 09:38 3fc98512-a92e-4e3b-9de7-556b8e206786
-> ../../sda1
lrwxrwxrwx 1 root root 10 Apr 27 09:38 64b8ae66-cf37-4676-bf9f-9c4894788a7f
-> ../../sda7
lrwxrwxrwx 1 root root 10 Apr 27 09:38 96254af9-7fe4-4ce0-886e-2e25356eff81
-> ../../sda5
lrwxrwxrwx 1 root root 10 Apr 27 09:38 ae616b82-35ab-4f7f-9e6f-3c65326d76a8
-> ../../sda4
dm-0 | busy 90% | | read 2516 | write 0 |
| KiB/r 512 | KiB/w 0 | | MBr/s 125.8 | MBw/s 0.0
| | avq 10.65 | avio 3.57 ms | |
LVM | dm-1 | busy 80% | | read 2406 | write
0 | | KiB/r 512 | KiB/w 0 | | MBr/s
120.3 | MBw/s 0.0 | | avq 12.59 | avio 3.30 ms |
|
DSK | sdc | busy 90% | | read 5044 | write
0 | | KiB/r 256 | KiB/w 0 | | MBr/s
126.1 | MBw/s 0.0 | | avq 19.53 | avio 1.78 ms |
|
DSK | sdd | busy 80% | | read 4805 | write
0 | | KiB/r 256 | KiB/w 0 | | MBr/s
120.1 | MBw/s 0.0 | | avq 23.97 | avio 1.65 ms |
|
DSK | sda | busy 0% | | read 0 | write
7 | | KiB/r 0 | KiB/w 10 | | MBr/s
0.0 | MBw/s 0.0 | | avq 0.00 | avio 0.00 ms |
|
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