Brian Vagnoni on 16 Nov 2009 11:54:09 -0800

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Re: [PLUG] To Drop or Not Drop Caches

----- Original Message -----

> Can you give more background about how caching filesystem data in
> unused memory 
> is substantially slowing down your system (hardware, application
> requirements, 
> how caching was determined to be the problem, etc.)?

----- Original Message -----

First, thanks for the response. 

It's a VMware Workstation 7 guest VM, running Opensuse 11.1, on a Win2003R2 Server Host. I have a U320 disk array with a pre-allocated 35gb disk, at roughly 50% full on all partitions. I have 2 2.8GHz Opterons, out of 4 on the host, and 3GB of memory alloted the VM, out 7GB on the host. I have a 2gb swap file, and got my swap on :-). I have it operating in bridged mode with a WAN address, and no LAN. 

I mainly run openvpn, ssh, http, and webmin, irc cleints, x11 forward, & vnc, behind the firewall. It's a part time desktop, and secure remote gateway for me. 

So what I initially noticed was a slow to respond desktop. When I looked at the u320 cage, all of the drive lights were flashing away for long periods, more so that usual, for my light load. I checked the Opensuse sysinfo page, and saw that the system caches had eaten up on the free ram, leaving me only 80MB available. So I rebooted to see if that took care of the problem, and started watching the cache size. The cache once again, though very slowly, started increasing in size, and the free memory deceased in size. 

Applying the commands mentioned in the wiki helped, and we are back to zippy again

right now here is what free shows:

# free
             total       used       free     shared    buffers     cached
Mem:       3145000    1032788    2112212          0      30520     391276
-/+ buffers/cache:     610992    2534008
Swap:      2104472          0    2104472

Brian Vagnoni
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