In my experience the defaults give far from the best performance.

Ofcourse, this always depends on the actual configuration, and the only 
way to
get the best performance is to test your environment.

Setting hi receive and transmit windows in Linux usually gives some speed, 
and
uselargebuffers/largecommbuffers/tcpnodelay in dsm.sys often gives speed
improvements.

As I recall tcpwindowsize is maxed at 128 in Linux and tcpbuffsize 512.

txngroupmax gives speed improvement and should be changed depending on if 
your'e
sending directly to tape or disk.

The most important thing is ofcourse trying to use as many sessions as 
possible
(resourceutilization). Try breaking up large filesystems with 
virtualmountpoints.

For more tips, check out IBM's performance tuning guide at
http://publib.boulder.ibm.com/tividd/td/TSMM/SC32-9101-01/en_US/HTML/SC32-9101-01.htm

Theres also alot of guides for tuning Linux sysctls out there.

-David

--
David Hendén
Exist AB, Sweden




"Hougaard.Flemming FHG" <FHG AT KMD DOT DK> 
Sent by: "ADSM: Dist Stor Manager" <ADSM-L AT VM.MARIST DOT EDU>
2006-02-10 00:44
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Subject
Best practice for linux backup






Hi all

Anyone got any ideas for a "best practice" for backup of linux servers
to increase performance?? Typically the backup will be done over WAN
links of 2-100 Mbit.

I'm thinking TCPWINDOWSIZE, TCPBUFFSIZE etc... is the default values
good enough? Or do I have to fine tune here?

Regards
Flemming




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