Subject: Thunderbird causing system crash, need guidance

[Matthew Seaman]

On 11/12/2017 04:56, Gary Aitken wrote:

>>> md99                  none  swap    sw,file=/usr/swap/swap,late
0       0

>> Your swap configuration is also mostly likely silly.  If you need
>> more performance, that's not the way to do it.

> Can you explain or point me to an explanation for this comment?  It
> looks to me like what's shown in the EXAMPLES section of "man fstab".

You're swapping to a file-backed memory device, which is not the best
choice for performance.  The best choice is to swap to raw partitions on
your hard drives.  Having several disks with a swap partition on each
can help, as it allows you to spread the IO load over several devices,
but that's a marginal gain and not necessary in general.

The reasoning being that you're involving all of the kernel machinery to
support filesystem IO for what is meant to be the very low-level and
simplified operation of paging memory in and out of swap.

Yes, you can create a file-backed swap area, but just because you can
doesn't mean you should.  Creating a file-backed swap is useful in
special cases, like you're working on that part of the kernel and need
to test adding or removing swap devices, or you're trying to cope with
some exceptional process that is really far too large for your system to
handle.

Ideally nowadays you should have enough RAM to contain all of your
active processes without needing to swap, so the whole point should
really be moot.

	Cheers,

	Matthew




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