On 07/15/15 19:39, Brett Lymn wrote:
On Wed, Jul 15, 2015 at 04:32:45PM -0453, William A. Mahaffey III wrote:dump device configured. I have 6 swap partitions:That seems a bit excessive - the days of "2 * physical RAM plus a bit" for swap allocation has not been needed for quite some time. I guess in the general scheme of things the amount of storage you have allocated for swap is not much but, still, it really doesn't need to be that much IMHO. Also, why are they not a raid? At the moment if you lose a disk that hosts the swap chances are the machine will go down.
Good questions. I have always heard that you get the best swasp performance w/ the raw kernel driver (under SGI & linux), rather than swapping to a RAID device. I have another box (Linux, FC14 64-bit) that swaps to a RAID device, & it takes several min. to page in a few hundred MB of paged-out-VM. That may be a linux only issue, but it is consistent w/ my historical recollections. I have 96 GB of swap & 64 GB of RAM. When fully operational the box may spend some time doing large CFD calculations which exhaust that amount of RAM (pretty easy to do, actually). The process should be able to continue, albeit more slowly, which I will need. The swap devices are 1 slice on each of 6 HDD's, for max parallelism & hopefully max performance. As soon as this machine is fully up & running, I am going to redo the linux box to get rid of swapping on a raid device (& allocate disk-space more usefully), & will be going back to swapping on raw partitions due to crappy performance of swap-on-raid on that box. The HDD's are brand new 2.5" drives, which I have had good luck with historically, so I am hoping for more of the same WRT HDD reliability vis-a-vis swapping (& other data partitions).
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William A. Mahaffey III
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