One point that I seem to find when dealing with Linux memory. Just how much?
We keep hearing recommendations of 256 MBs or 560 MBs. Some of these recommendations are needed during the install of Linux (Suse likes memory as it uses a ram disk to start off with). And yes, Websphere, from what I hear, needs a lot of memory. Perhaps a database, depending on the number of requests needs a lot of memory. But a lot of other stuff, really doesn't seem to need memory. I've started down a path to see just how little I need. Using "free" and "vmstat 10 100" I monitor how much virtual memory is free and how much swap space is used. With the default Suse 8 distribution, I can IPL and do some work with 16 MBs virtual, without a swap disk. With a swap disk, I have yet to hit a large enough work load that I ran out of space. FTPs, gpg, text editing, all seem to work fine with 16 MBs virtual. Perhaps performance could be better, but, so far, the FTPs and gpg encriptions are basically a single threaded workload (all running under Regina 'REXX'). Perhaps Samba would need more. But if it is just using the memory for cache, just how many users are accessing the same files? If not a lot, the cache hit would be low. Trim down the machine. Let VMs MDC take care of cache hits. Since real memory is my biggest constraint, I want the machines to be lean, mean, fighting machines. I don't want them to time out. But I don't want taking real storage away for, what turns out to be useless crap, from affecting my other production machines. Trim them down. Monitor with "free" and "vmstat" the space used on the swap disk. See how well they run. Even if you can only trim the Samba machines down to 64 MBs, you can run another 3, 64 MB machines with the same memory footprint. TEST SYSTEMS! What a concept. Tom Duerbusch THD Consulting >>> [EMAIL PROTECTED] 06/11 1:02 PM >>> We're running SLES7 and have two Samba servers for our department with 50-75 users, 25GB of disk storage each, and they run very well with only 48M of virtual storage and 128M of V-disk swap. "Great Minds discuss ideas. Average minds discuss events. Small minds discuss people." - Admiral Hyman Rickover Gordon Wolfe, Ph.D. (425)856-5940 VM Enterprise Servers, The Boeing Company > ---------- > From: Lionel Dyck > Reply To: Linux on 390 Port > Sent: Wednesday, June 11, 2003 6:41 AM > To: [EMAIL PROTECTED] > Subject: VM Memory for Samba > > How much memory should be allocated to a Linux guest by z/VM that is doing > only Samba for file serving? > > Does it matter how many users? Est is between 200 and 2000 per instance. > > thx > -------------------------------------------------------------------- > Lionel B. Dyck, Systems Software Lead > Kaiser Permanente Information Technology > 25 N. Via Monte Ave > Walnut Creek, Ca 94598 > > Phone: (925) 926-5332 (tie line 8/473-5332) > E-Mail: [EMAIL PROTECTED] > Sametime: (use Lotus Notes address) > AIM: lbdyck > >
