Hello,
Has anyone some experience using defragmentation tools on Linux against tablespaces ?
we are facing fragmentation problems with postgres instances having a few TB of data.
( RAID 5 )
I/O througput decreased from 300MB/s to 160.
- We first moved some schemas to separate servers.
After that we still have 150'000 tables in 1.5 TB
- Now we are in the process of vacuuming FULL historical tables which are not written anymore.
This seems to improve the I/O considerably
Our remaining issue is that the free space fragmentíon is still suboptimal
so that fragmention will probably start again soon.
Would it make sense to use a tool like e4defrag
(http://www.linux.org/threads/online-defragmentation.4121/)
in order to defrag the free space ?
And how safe is it to use such a tool against a running postgres instance?
many thanks,
Marc Mamin
