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x0500hl
14-Sep-2017, 15:05
Last week I performed an upgrade in place on one of my virtual servers that run under z/VM 6.4. I upgraded from SLES 11 SP4 to SLES 12 SP2.

My servers are all set up with at least 2 swap disks. One is a small (256MB) virtual swap disk and a 3390 mod9 (7048MB) swap disk. The virtual swap disk is supposed to be the primary disk. After the upgrade the physical disk is the primary, but /etc/fstab shows that it should not be.

Output of a section of 'lsdasd':

Bus-ID Status Name Device Type BlkSz Size Blocks
================================================== ============================
0.0.0201 active dasda 94:0 FBA 512 100MB 204800
0.0.0200 active dasdb 94:4 ECKD 4096 7042MB 1802880
0.0.0202 active dasdc 94:8 ECKD 4096 7042MB 1802880

Output of a section of /etc/fstab:

/dev/disk/by-path/ccw-0.0.0201-part1 swap swap pri=-1 0 0
/dev/disk/by-path/ccw-0.0.0202-part1 swap swap pri=-2 0 0

Output of 'swapon -s':

Filename Type Size Used Priority
/dev/dasdc1 partition 7211420 19496 -1
/dev/dasda1 partition 101536 0 -2

Any idea why SLES 12 is not honoring the values specified in /etc/fstab? What setting(s) do I need to modify to have the swap priorities set as specified in /etc/fstab?

Harley

x0500hl
19-Sep-2017, 20:22
I found the problem! SLES 12 is now enforcing a range limit on the pri= value specified in /etc/fstab.

From /var/log/messages:

2017-09-05T18:36:33.401209-05:00 wcs-mf-winxs-db2t systemd[1]: Failed to parse swap priority "pri=-2", ignoring: Numerical result out of range
2017-09-05T18:36:33.401211-05:00 wcs-mf-winxs-db2t systemd[1]: Activating swap /dev/disk/by-path/ccw-0.0.0202-part1...
2017-09-05T18:36:33.401214-05:00 wcs-mf-winxs-db2t systemd[1]: Failed to parse swap priority "pri=-1", ignoring: Numerical result out of range
2017-09-05T18:36:33.401217-05:00 wcs-mf-winxs-db2t systemd[1]: Activating swap /dev/disk/by-path/ccw-0.0.0201-part1...

Unfortunately, it is enforcing the wrong range. Here is the 'pri=' sections from the man page for swapon(8), on SLES 12 SP2:

-p, --priority priority
Specify the priority of the swap device. priority is a value between -1 and 32767. Higher numbers indicate higher priority. See swapon(2) for a full description of
swap priorities. Add pri=value to the option field of /etc/fstab for use with swapon -a. When no priority is defined, it defaults to -1.


Harley