All-
We are having trouble backing up a couple of quite large file systems served to us by a Network Appliance filer via nfs mounted access. The backup system involved is TSM. The operating system controlling all this is RHEL 4.3 WS. The mount options are specified in fstab as 'defaults'. These file systems are large in the sense of many files ( 8 - 10 million of them ) each quite small. Not a huge amount of data as such. Also the directory tree is both deep and wide. We are backing up other file systems of less files of larger size, and in total more data, just fine. But these bog down while the backup is building the worklist ... lots of directory tree walking but not much data transfer yet. It seems to start out fine, handling many objects per unit time, but the longer it runs the slower it gets until just a trickle of objects per unit time. I seem to have some memories of nfs doing some throttling under loads like this, but cannot remember details. I am also remembering something about file system drivers not handling i/o request queues all that well, but again am missing details. So ... 1) am I remembering right?; 2) are there nfs knobs to turn that might help this?; 3) are there file system knobs to turn that might help this?; 4) any network related settings that can help?; 5) any other suggestions that might help tune this? It is getting to where it takes more than 24 hours to back up a days work ... a losing proposition if I do say so myself.
Thanks,
Wilville
We are having trouble backing up a couple of quite large file systems served to us by a Network Appliance filer via nfs mounted access. The backup system involved is TSM. The operating system controlling all this is RHEL 4.3 WS. The mount options are specified in fstab as 'defaults'. These file systems are large in the sense of many files ( 8 - 10 million of them ) each quite small. Not a huge amount of data as such. Also the directory tree is both deep and wide. We are backing up other file systems of less files of larger size, and in total more data, just fine. But these bog down while the backup is building the worklist ... lots of directory tree walking but not much data transfer yet. It seems to start out fine, handling many objects per unit time, but the longer it runs the slower it gets until just a trickle of objects per unit time. I seem to have some memories of nfs doing some throttling under loads like this, but cannot remember details. I am also remembering something about file system drivers not handling i/o request queues all that well, but again am missing details. So ... 1) am I remembering right?; 2) are there nfs knobs to turn that might help this?; 3) are there file system knobs to turn that might help this?; 4) any network related settings that can help?; 5) any other suggestions that might help tune this? It is getting to where it takes more than 24 hours to back up a days work ... a losing proposition if I do say so myself.
Thanks,
Wilville
