Hi All
We use CentOS 6.6 for our application. I have profiled the application
and find that we have a heavy requirement in terms of Disk writes. On an
average when our application operates at a certain load i can observe
that the disk writes / second is around 2 Mbps (Average).
The block size set is 4k
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[root@localhost ~]# blockdev --getbsz /dev/sda3
4096
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OS , Kernel Version:
*****************
[root@localhost ~]# uname -a
Linux localhost 2.6.32-504.el6.x86_64 #1 SMP Wed Oct 15 04:27:16 UTC
2014 x86_64 x86_64 x86_64 GNU/Linux
[root@localhost ~]# cat /etc/*release
CentOS release 6.6 (Final)
CentOS release 6.6 (Final)
CentOS release 6.6 (Final)
*****************
File-System being used:
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[root@localhost ~]# df -T
Filesystem Type 1K-blocks Used Available Use% Mounted on
/dev/sda3 ext3 100934056 20298152 75508688 22% /
/dev/sda1 ext3 198337 34459 153638 19% /boot
tmpfs tmpfs 16440152 0 16440152 0% /dev/shm
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I have a few queries with respect to the block size being set in the system:
1. Is 4k the optimum block size considering the amount of writes /
second the application performs ?
2. How do i find out the optimum block size given the application load
in terms of reads / writes per second ?
3. If there is a better block size that i can use , Can you suggest one ?
4. What are the pros / Cons of changing the default block size ?
5. We use ext3 as the file system for the partition which has heavy
writes per second , Should we migrate it to ext4 ? Any pros / cons for it ?
Appreciate any response / pointers in this regard.
Thanks
Jatin
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