Re: Swap space not used
On Thu, 03 May 2012 03:48:59 -0400 (EDT), Claudius Hubig wrote:
>
> Stephen Powell <zlinuxman@wowway.com> wrote:
>> It is my understanding that,
>> assuming suspend/resume is supported, your swap partition
>> should be AT LEAST as large as TWICE the amount of RAM.
>> Suspend/resume will consume a RAM's worth right out of the
>> starting gate. The rest is then available for regular swap
>> file activity.
>
> This is - more or less - wrong. Suspend/Resume will consume at most
> swap space corresponding to the used RAM (i. e. with compression and
> dropping of buffers/caches, it can be far less). However, this swap
> space is not used during runtime but only on suspend, so if there is
> no need to suspend under heavy load (used swap usually indicates
> heavy load on a desktop and I fail to imagine a reason why you’d like
> to suspend a server…), swap the size of RAM is definitely enough.
Thank you for explaining this. I was making an assumption based
on previous experience with other operating systems that is
apparently not warranted. For example, z/VM will allocate its
dump space in the system spool during startup, just to make sure
that if it needs to take a dump, there will be sufficient spool
space available to do it. The size of the dump space is based on
the amount of RAM, of course. (Or as mainframers call it, CSTORE.)
Of course, a system dump and a suspend image are taken for different
purposes, but both involve a dump of RAM.
--
.''`. Stephen Powell
: :' :
`. `'`
`-
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