Change size journal's blocks from 4k to another.

[Mike <mike.almateia@gmail.com>]

Hello.

I am also sent this message to ceph-users@ maillist, but nobody answer
me. If this topic is inappropriate for this maillist I am already to
apologize.

In my Ceph installation I am uses a ssd drive for journal with direct
access.

When an osd started I see in log file this string:
...
1 journal _open /dev/sda1 fd 22: 19327352832 bytes, block size 4096
bytes, directio = 1, aio = 1
...

How I can change size of block from 4k to 512k, because my SSD show
better perfomance witch large blocks:
* With 4K (sdr6 - source, sda8 - target)

dd if=/mnt/from/random of=/mnt/sda8/random bs=4k oflag=direct,dsync

iostat show me the statistic:
iostat -cdm 1 /dev/sda /dev/sdr

Device:            tps    MB_read/s    MB_wrtn/s    MB_read    MB_wrtn
sda           16198.00         0.00       126.54          0        126
sdr             126.00        15.75         0.00         15          0


* With 512K (sdr6 - source, sda8 - target)
Sync: sync
Clear cache: echo 1 > /proc/sys/vm/drop_caches
Clear cache LSI controller: megacli -AdpCacheFlush -a0

dd if=/mnt/from/random of=/mnt/sda8/random bs=512k oflag=direct,dsync

iostat show me the statistic:
iostat -cdm 1 /dev/sda /dev/sdr

Device:            tps    MB_read/s    MB_wrtn/s    MB_read    MB_wrtn
sda            3021.00         0.01       318.00          0        318
sdr            2410.00       301.25         0.00        301          0

I think my cluster have a bottle neck in journal block size. How I can
increase the size of block for journal?

--
Best regards, Mike.