[nmglug] Raid Help

[Tim Emerick]

I need some help with my Debian/samba server with regards to raid
performance.

I get pretty fast reads but extremely slow writes.  A folder with 116MB took
38 seconds to read from the server but 5 minutes 18 seconds to write to the
server.  I've heard that fast reads and normal writes is fairly typical with
a simple mirror raid but the slowness of my writes are ridiculous.  

I think I probably have something mis-configured.  I would like to have a
conversation with someone that can help me figure out either what is wrong or
what I can do to get better performance. Please feel free to contact me in
person or chat for a more "Live" discussion. I would greatly welcome any
help.

Tim Emerick
Reliable Chevrolet
505-338-5848
aim: timemerick
yahoo: timothyemerick
timothyemerick at yahoo.com

Here are some stats:

Machine is a P4-1.5ghz with 2 80gb HD's sitting on a SiL raid card using
raid1/mirror (/dev/hde1 & /dev/hdg1 raided as /dev/md0) and a 160GB drive
(/dev/hda6) for rolling backups.

Roughly 100 casual users and 5 heavy database users.  

Currently Swat reports about 30 active connections, 30 active shares, and 450
open files.

# cat /proc/meminfo
MemTotal:       256944 kB
MemFree:          5276 kB
Buffers:         13660 kB
Cached:         175668 kB
SwapCached:          0 kB
Active:          47600 kB
Inactive:       162768 kB
HighTotal:           0 kB
HighFree:            0 kB
LowTotal:       256944 kB
LowFree:          5276 kB
SwapTotal:      746980 kB
SwapFree:       746980 kB
Dirty:             256 kB
Writeback:           0 kB
Mapped:          28628 kB
Slab:            37180 kB
Committed_AS:    67328 kB
PageTables:        724 kB
VmallocTotal:   778160 kB
VmallocUsed:      2616 kB
VmallocChunk:   775044 kB

# df -h
Filesystem            Size  Used Avail Use% Mounted on
/dev/hda1             6.5G  576M  5.6G  10% /
tmpfs                 126M     0  126M   0% /dev/shm
/dev/hda6             140G  109G   24G  83% /backup
/dev/md0               74G   29G   42G  41% /shares

# cat /proc/loadavg
0.00 0.00 0.00 3/66 14525




		
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