Windows Server 2003 for 64-Bit Extended Systems
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Bad Performance on write to initialy opened file

Volker Borowski
Honored Contributor

Bad Performance on write to initialy opened file

Hello,

Anyone ever observed this ?

# I have a plain Text file of 22MB

E:\>dir 22MB.txt
04.09.2008 09:54 22.513.800 22MB.txt

# I have a Script, that initialy redirects this File
# to another server, appends the same file
# to the same target file on the remote server
# and once again writes this file initially
# by overwriting the first file again
# in between i simply "echo" the %TIME% variable
# to do some measurement
# Servers are GB connected, same slot card
# in the very same switch

E:\>testit

E:\>echo 11:00:01,05
11:00:01,05

E:\>type 22MB.txt 1>\\rserver\e$\murks

E:\>echo 11:00:44,47
11:00:44,47

# initially opened the file with ">"
# now ~ 43 secs for 22 MB is pretty bad

E:\>type 22MB.txt 1>>\\rserver\e$\murks

E:\>echo 11:00:47,10
11:00:47,10

# Same file appended
# ~2,5 sec which is ~ 17 times faster

E:\>type 22MB.txt 1>\\rserver\e$\murks

E:\>echo 11:01:29,30
11:01:29,30

# same file again with overwrite
# Once Again 43 Seconds

Boxes have W2K3 SP2 and current patches with Intel 1000 PRO/1000 MT Lan adapters. Situation occurs on either connections between Domain Member Servers or two standalone servers

Why does the initial OPEN Call is so expensive and the append so cheap?

Additional tests with
Doing the same thing on a local share results
in all three actions beinge performed in
~ 5 seconds each (source and target on same disk)
Doing the same thing on a local drive (no UNC Path) results in all three actions beinge performed in
~ 1.5 seconds each (source and target on same disk)
~ 1.5 seconds each (source and target on diffrent disk)

Is anyone aware of a patch, that fixes this, which I might have missed?

Comments highly appreciated
Volker
2 REPLIES
Chris Ciapala
Trusted Contributor

Re: Bad Performance on write to initialy opened file

Not really help, just few thoughts.
Do you use antivirus on target server? I recently tested Symantec Endpoint and also I got pretty strange results. Other things which might affect this: compression on target filesystem, quotas (not really, but..), firewalls or antispyware realtime scanners.
You can also check how is your server service configured (file server, application, balance...) and test with different settings.
Volker Borowski
Honored Contributor

Re: Bad Performance on write to initialy opened file

Hi,

no anti Virus Software in place.
Server is either configured for best performance / Throughput for network applications (tried SP1 and SP2).
Same behavior on a Fileserver with SP2 (Not tried with SP1 there).

It can not have anything to do with metall I think, because the "append" access is pretty fast.

Volker