Backing up data from an hp735 took more than 7 hrs. I had concurrency set to 4 and data compression

[lastgreatone]

Backing up data from an hp735 with a 10Mbit NIC, took more than 7 hrs to a DLT8000 on an L-class. I had concurrency set to 4 and data compression set on. It initially started backing up at an acceptable speed but then crawled to almost a halt when it started backing the NFS mount point. I have set concurrency to 1 and I have removed the compression. Anything other pointers would be helpful.

TIA

[Ovidiu D. Raita]

Francoise,

I think I'd need some more info to find exactly the problem ( data size, number of files/file system, the speed of a ftp between L and 735) but a can guess that your main problem is NFS.

NFS is very bad in performance when tranfering a large number of small files. Beside this NFS uses the same network (10MB) as the backup server and that's even worse.

A good example of file systems that NFS has problem transfering with is the OS itself. It has enough files to kill NFS.

Ovidiu

[Alan Riggs]

1) Your problem is almost certainly the NFS mount. It is at teh least conflicting for access on your local subnet. If you are mounting from anoher box not on your subnet, you also have that additional network lag to deal with. If the box is under your control I suggest excluding the NFS mount fromm this host's backup and adding a filesystem backup of the local mountpoint on the NFS host. If the NFS server is not under your control, whoever administers that box should be responsible for backing up data.

As a side note: network backups are the one time you *should* use software compression. It is generally less efficient than hardware compression for sheer bit-packing, but is drastically reduces the amount of data you have to pass over a slow wire.

[Paula J Frazer-Campbell · Accepted solution]

Hi
Are you running the same level of NFS on both machines as the NFS2 to NFS3 connectivity has problems.

10.20 - NFS2
11.00 - NFS3

If this is the problem either ugrade the os to match or download and install NFS3.


HTH
Paula