Hi bcache team,
we are currently developing performance test scripts with Fio for bcache.
At the end of a test we want to detach and destroy the cache. Therefore we did:
echo 1 > /sys/block/$dev/bcache/detach
echo 1 > /sys/block/$dev/bcache/stop
echo 1 > /sys/fs/bcache/*/stop
echo 1 > /sys/fs/bcache/*/unregister
With a simple randwrite test with we had about 2GB dirty data in the cache. After detaching the dirty data flush rate was about 900KB/s from SSD to HDD.
Is there a way to accelerate flushing of dirty data?
What is the correct way to detach/destroy a writeback caching device?
* Kernel: 3.11.0-2-generic #5-Ubuntu SMP Mon Aug 12 16:09:51 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux
* Kernel module info:
filename: /lib/modules/3.11.0-2-generic/kernel/drivers/md/bcache/bcache.ko
author: Kent Overstreet <kent.overstreet@xxxxxxxxx>
license: GPL
license: GPL
author: Kent Overstreet <koverstreet@xxxxxxxxxx>
srcversion: EE441BF41AAB31C3E44F5D2
depends:
intree: Y
vermagic: 3.11.0-2-generic SMP mod_unload modversions
* iostat while flushing after detach:
Device: tps kB_read/s kB_wrtn/s kB_read kB_wrtn
sda 0.00 0.00 0.00 0 0
sdc 229.50 912.00 6.00 1824 12
sdb 228.00 0.00 912.00 0 1824
bcache0 0.00 0.00 0.00 0 0
Thanks a lot for your help in advance, Georg.
--
: Georg Schönberger
: Research & Development Executive
: Thomas-Krenn.AG | The server-experts
: http://www.thomas-krenn.com | http://www.thomas-krenn.com/wiki
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