Swap is in use by Live Upgrade!!!

Just now working on few ZFS post migration cleanup task like creating new ZFS filesystems which are currently on UFS SVM devices, rsync them, ludelete the UFS BE and finally add empty disk to the rpool. While working on this I encountered an error while deleting the swap space holding one of the soft partition.


I was in a process of clearing the metadevices and one of the soft partition holding 32G of swap space and system was not allowing me to delete it. The error I was getting was –

# swap -l
swapfile dev swaplo blocks free
/dev/md/dsk/d34 85,34 16 67108848 67108848

# swap -d /dev/md/dsk/d34
/dev/md/dsk/d34: Not enough space

This was obvious because system was using this swap as a active swap.

# top -c
last pid: 5639; load avg: 3.78, 3.40, 3.41; up 25+15:39:04
1327 processes: 1258 sleeping, 64 zombie, 5 on cpu
CPU states: 91.0% idle, 2.5% user, 6.5% kernel, 0.0% iowait, 0.0% swap
Memory: 96G phys mem, 14G free mem, 32G swap, 32G free swap

Then I was wondering, where is my ZFS swap volume gone? Why system is not using this volume? So I tried making it active using swap -a but I failed to do it & system gave me below message.

# swap -a /dev/zvol/dsk/rpool/swap
/dev/zvol/dsk/rpool/swap is in use for live upgrade -. Please see ludelete(1M).

Okay, so this was first time ever that happened to me. Well after scratching my head on wall for a while I got the answer.

The swap -a attempt might fail if the swap area is already listed in /etc/vfstab or is in use by Live Upgrade. In this case, use the swapadd feature instead.

# /sbin/swapadd


# swap -l
swapfile dev swaplo blocks free
/dev/zvol/dsk/rpool/swap 256,1 16 2097136 2097136

# top -clast pid: 13969; load avg: 2.34, 2.66, 2.84; up 25+16:07:28
1321 processes: 1255 sleeping, 64 zombie, 2 on cpu
CPU states: % idle, % user, % kernel, % iowait, % swap
Memory: 96G phys mem, 12G free mem, 64G swap, 64G free swap

All right then, sometimes it’s good to scratch your head on wall for a while… :) isn’t it?

HTH