I'm down to 75% usage now and write speeds in the root of that filesystem are still 5MB/sec. I do have a directory that gives me 180MB/sec writes -- I suppose it has a big set of contiguous blocks assigned to it.
On most files, cp fraggedfile fraggedfile2 and using filefrag to check extents usually results in a much less fragmented file, as long as I keep freeing space while copying files, anyway. The highest I've found so far had 110,000 extents. It's down to 1000 now, which is still incredibly high but not as obscene. I had a directory of a thousand photos that were each using 300+ extents. cp those files into a new dir and now they're each using 1 as is desired. The goal now is just to get the usage on the drive to a low enough level that I can load off the remaining data onto a new drive and remake that filesystem. Something obviously went very wrong there. On 1/19/07, Jason Fisher <[EMAIL PROTECTED]> wrote: > I'm at 99% right now (30GB free) -- I'll free some space, test again every > 5% and report back. > > Interestingly, a dd if=/dev/zero of=fragtest bs=40k count=1;filefrag > fragtest results in that file using 3 extents instead of 1 roughly every > 10th-11th creation. > > Just for reference, a fresh JFS on the same 7-disk RAID5/LVM partition gets > 185MB/sec writes consistently. > > Thanks for the help, > Jason > > > On 1/19/07, Dave Kleikamp <[EMAIL PROTECTED]> wrote: > > On Fri, 2007-01-19 at 01:38 -0500, Jason Fisher wrote: > > > I have a 1.6TB jfs partition (Linux) that is roughly a year old. In > > > this time, the write speed has managed to drop to 5MB/sec and it has > > > become nearly unusable. I mainly use the RAID for mythtv, but > > > recently it has become too slow for capturing. > > > > > > filefrag reports some 3GB files with 90,000 extents next to 3GB files > > > with 18 extents. Many files with thousands of extents. > > > > > > I understand there are no defrag tools available for Linux, and I > > > would rather not back the data up and restore as it's important, but > > > just not important enough to warrant the time spent. > > > > > > Is there another way I can deal with these files? > > > > > > I copied a file with 3000 extents off the partition and onto a spare, > > > deleted the original and copied the file back and ended up with 1100 > > > extents. An improvement, but would this method ever get performance > > > back to a usable level? > > > > I'm not sure if this will make much of a difference. Defragging the > > existing files one at a time may not have much of an effect on the > > remaining free space, so a new file being captured may be just as > > fragmented as before. > > > > > What if I were to fill the remaining space > > > with dd after deleting the original/before copying it back? > > > > I don't think this will do anything useful. > > > > > Or should > > > I concentrate on freeing up as much space as possible before copying > > > any files to/from? > > > > The more free space you have, the better. I don't know how close to > > full your disk is, but you may want to try to maintain a certain amount > > of free space and see how that affects performance. If you do find a > > "sweet spot" such as having good performance when the disk is say 80% > > full, I'd be interested to know that. Hopefully that percentage isn't > > too low. > > > > > Thanks, > > > Jason > > -- > > David Kleikamp > > IBM Linux Technology Center > > > > > > ------------------------------------------------------------------------- Take Surveys. Earn Cash. Influence the Future of IT Join SourceForge.net's Techsay panel and you'll get the chance to share your opinions on IT & business topics through brief surveys - and earn cash http://www.techsay.com/default.php?page=join.php&p=sourceforge&CID=DEVDEV _______________________________________________ Jfs-discussion mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/jfs-discussion
