|To:||Ying-Hung Chen <ying@xxxxxxxxxxxxxx>|
|Subject:||Re: howto preallocate to minimize fragmentation|
|From:||Eric Sandeen <sandeen@xxxxxxx>|
|Date:||Thu, 22 Sep 2005 09:40:08 -0500|
|References:||<43329839.2070005@xxxxxxxxxxxxxx> <4332A22B.6070708@xxxxxxx> <4332BFCC.8050803@xxxxxxxxxxxxxx>|
|User-agent:||Mozilla Thunderbird 1.0 (X11/20041206)|
Ying-Hung Chen wrote:
See the xfsctl man page from xfsprogs, specifically XFS_IOC_RESVSP creating a sparse file will not help with fragmentation, unfortunately.Hello again, Thanks for the info, here are more specifics on what we are trying to do: we have 200GB of harddive and would like to create 90-95 of 'video' file, each with 2GBs (data will be writting to each file continuesly, just like a tape). and we are hoping that if can write to the same physical place all the time, there won't be any fragmentation problem.... we are wondering if there are any xfs parameters we can do (e.g. volumes groups?) for the above to 'gaurantee' the best layout since we are not going to create/delete files once created all those Video files, all we are doing are overwriting files continuesly.
pre-allocation before writing would still be your best bet. If you pre-allocate on a fresh fs before writing, you should get very large extents.
Other things you could try; if you put each file in its own dir, it will tend to go into its own allocation group.
You could make the filesystem with allocation groups sized at 2GB -Eric
|<Prev in Thread]||Current Thread||[Next in Thread>|
|Previous by Date:||Re: howto preallocate to minimize fragmentation, Ying-Hung Chen|
|Next by Date:||Re: howto preallocate to minimize fragmentation, Ying-Hung Chen|
|Previous by Thread:||Re: howto preallocate to minimize fragmentation, Ying-Hung Chen|
|Next by Thread:||Re: howto preallocate to minimize fragmentation, Ying-Hung Chen|
|Indexes:||[Date] [Thread] [Top] [All Lists]|