[Ocfs2-devel] About ocfs2 file sytem fragmentation tool

[Joseph Qi <joseph.qi@huawei.com>]

Hi Gang,
We can also get some information from
    "debugfs.ocfs2 -R 'stat //global_bitmap' <device>"
But unfortunately there is no summary information such as fragmentation
ratio.
We have encountered a problem that once volume usage exceeds 95%, create
a new big file will consume much longer time, which is because of each
gd in chains has little contiguous clusters.

Thanks,
Joseph


On 2016/8/11 14:03, Gang He wrote:
> Hello Guys,
> 
> Our customer is asking one question, how to detect a ocfs2 file system fragmentation status.
> Current, I can think of ways for detecting fragmentation as below,
> 1) o2info --freefrag N /dev/vdb3
> this command can give some information for how many free chunks (based on size) are here,
> but it can not give any conclusive information, e.g. the file system is fragmented, or not.  fragmentation ratio.
> 2) debugfs.ocfs2 -R "frag /fio1/test1"  /dev/vdb3
> this command can give some information only for one file, how to get the whole volume information, e.g. the file system fragmentation ratio.
> 
> So, anybody can give some suggestion for ocfs2 file system fragmentation tool, it is very appreciated.
> For example, there is any more better way to detect the file system fragmentation ratio.
> The further question, if there are some free blocks in the file system, but the user cannot create a file, it is also related to fragmentation problem?
> The use have to use "discontig-bg" feature to overcome this problem?
> 
> 
> Thanks
> Gang
> 
> 
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