I have been backing up my main Linux server onto a secondary machine via NFS. I use xfsdump like this: xfsdump -l 9 -f /machine/backups/fs.9.xfsdump / Over on the server machine, xfs_bmap shows an *extreme* amount of fragmentation in the backup file. 20,000+ extents are not uncommon, with many extents consisting of a single allocation block (8x 512B sectors or 4KB). I do notice while the backup file is being written that holes often appear in the extent map towards the end of the file. I theorize that somehow the individual writes are going to the file system out of order, and this causes both the temporary holes and the extreme fragmentation. I'm able to work around the fragmentation manually by looking at the estimate from xfsdump of the size of the backup and then using the fallocate command locally on the file server to allocate more than that amount of space to the backup file. When the backup is done, I look at xfsdump's report of the actual size of the backup file and use the truncate command locally on the server to trim off the excess. Is fragmentation on XFS via NFS a known problem? _______________________________________________ xfs mailing list xfs@xxxxxxxxxxx http://oss.sgi.com/mailman/listinfo/xfs
