Re: Speed of rm compared to reiserfs (slow) - and switching logdevices

[Török Edwin <edwintorok@xxxxxxxxx>]

On 2008-09-26 10:41, Török Edwin wrote:
> On 2008-09-26 02:54, Dave Chinner wrote:
>   
>> On Thu, Sep 25, 2008 at 11:16:35AM +0300, Török Edwin wrote:
>>   
>>     
>>> On 2008-09-25 03:27, Dave Chinner wrote:
>>>     
>>>       
>>>> On Wed, Sep 24, 2008 at 11:43:13AM +0300, Török Edwin wrote:
>>>>       
>>>>         
>>> Thanks for the suggestions, the time for rm has improved a bit, but is
>>> still slower than reiserfs:
>>>
>>> time rm -rf gcc
>>>
>>> real    1m18.818s
>>> user    0m0.156s
>>> sys     0m11.777s
>>>
>>> Is there anything else I can try to make it faster?
>>>     
>>>       
>> Buy more disks. ;)
>>
>> XFS is not really optimised for single disk, metadata intensive,
>> small file workloads.
>>     
>
> I have 6 disks, in raid10 :)
>   


I moved the logdevice to another disk (not part of RAID array), and now
the speed of rm is down to 30 seconds!

I didn't find any documentation on how to convert an XFS fs with
internal log device to use external, so I did the following:
# xfs_db -x /dev/mapper/vg--all-lv--opt
xfs_db>sb
xfs_db> write logstart 0
xfs_db> quit

The zero the logdevice, and mount using logdev=. This worked.

However if I now use xfs_repair on this filesystem it restores the
internal log. Is there a way to make this change permanent? (i.e. switch
permanently to using external log?)

Best regards,
--Edwin