On Mon, Sep 29, 2008 at 06:01:18PM -0700, Jean Dion wrote:
Do you have dedicated iSCSI ports from your server to your NetApp?
Yes, it's a dedicated redundant gigabit network.
iSCSI requires dedicated network and not a shared network or even VLAN. Backup cause large I/O that fill your network quickly. Like ans SAN today.
Backup are extremely demanding on hardware (CPU, Mem, I/O ports, disk etc). Not rare to see performance issues during backup with several thousands small files. Each small file cause seeks to your disk and file system.
As the number of files and size you will be impact. That means, thousand of small files cause thousand of small I/O but not a lot of throughput.
What statistics can I generate to observe this contention? ZFS pool I/O
statistics are not that different when the backup is running.
Bigger your file are more likely the block will be consecutive on the file system. Small file can be spread in the entire file system causing seeks, latency and bottleneck.
Legato client and server contains tuning parameters to avoid such small file problems. Check your Legato buffer parameters. These buffer will use your server memory as disk cache.
I'll ask our backup person to investigate those settings. I assume that
Networker should not be buffering files since those files won't be read
again. How can I see memory usage by ZFS and by applications?
Here is a good source of network tuning parameters for your T2000
http://www.solarisinternals.com/wiki/index.php/Networks#Tunable_for_general_workloads_on_T1000.2FT2000
The soft_ring is one of the best one.
Here is another interesting place to look
http://www.solarisinternals.com/wiki/index.php/Solaris_Internals_and_Performance_FAQ
Thanks. I'll review those documents.
