[CentOS] Swap Considerations

Tue Feb 27 03:39:47 UTC 2007
Mike McCarty <Mike.McCarty at sbcglobal.net>

Feizhou wrote:
> Mike McCarty wrote:
> 
>> I am considering installing CentOS 4.4, and am interested in
>> how best to set up. I have been using FC2 and helping administer
>> a Debian machine for a few years, but do not consider myself a
>> Linux guru.
>>
>> My current set up uses a /swap partition which is 2x my memory
>> size
> 
> 
> This is a completely false premise that has no basis in Linux or even in 
> verions of Solaris after SunOS4. Only SunOS4 *REQUIRED* swap be twice 
> the amount of RAM due to how its VM was implemented. The best of part of 
> this is that this is actually a part of the 'knowledge' that the LPI 
> examinations will examine you on.
> 
> With regards to swap, on servers you want to tune things such that swap 
> is NEVER used but do create some swap space to handle edge cases. On 
> desktops, create as much swap as you wish to handle firefox, thunderbird 
> or whatever memory hungry GTK application you have. Of course, the more 
> RAM you have, the merrier.

Of course. But I'm a laid-off engineer. If you like, I'd gladly take
donations for more RAM. In the meantime, this machine remains 256M.

This is a single-user desktop with no external access servers
like SSH, Apache, or NFS running. I have a firewall to enforce
no external access, which "stealths" all ports except the e-mail
port, which is denied.

I find that on my machine, memory usage often looks like this:

Mem:    248088k total,   244192k used,     3896k free,    11860k buffers
Swap:   524120k total,   182916k used,   341204k free,    43576k cached

[snip]

> I would therefore put at least /home and /var on separate partitions if 
> it were a server where /home had data. If not, /var will be on its own. 
> If it were my home desktop, /home definitely gets its own partition.

Thanks for the reply.

Mike
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