[OpenIndiana-discuss] SSD as a dedicated swap device

[Ian Collins]

Reginald Beardsley via openindiana-discuss wrote:
> I have only occasional need to  run problems larger than main memory
 > (16 GB at present), so I can't justify replacing all the DRAM for an
 > infrequent need. The drop in SSD prices has me contemplating adding
 > a 128 GB SSD as a swap device. The SSD latency and IOPS specs look
 > as if they might be a useful compromise.
 >
 > Does anyone have any experience with this? The sort of jobs I'm
 > interested in are batch processes that take several hours, not
 > interactive tasks.

Even an SSD will be way slower than RAM..

> At present rpool is a ZFS 3 way  mirror. It's become a bit unclear to
 > me if it is still possible to control the swap device independently
 > of other parts of the system contained in rpool. Back in SunOS 4.x
 > days I ran with a pair of swap partitions spread across two disks
 > which got me twice the performance on large array operations.

I don't think you can add the drive as a drive, but you could create a 
pool with a single volume on on it and add that volume with "swap -a 
/dev/zvol/dsk/<pool>/<volume>.

-- 
Ian.