If a zpool is "UNAVAIL" during the run of 800.scrub-zfs, the
daily run will fail with messages like this:
Scrubbing of zfs pools:
usage: date [-jnRu] [-d dst] [-r seconds] [-t west] [-v[+|-]val[ymwdHMS]] ...
[-f fmt date | [[[[[cc]yy]mm]dd]HH]MM[.ss]] [+format]
expr: syntax error
[: -lt: unexpected operator
starting scrub of pool 'pool0':
cannot scrub 'pool0': pool is currently unavailable
consult 'zpool status pool0' for the result
skipping scrubbing of pool 'sys':
last scrubbing is 1 days ago, threshold is set to 7 days
usage: date [-jnRu] [-d dst] [-r seconds] [-t west] [-v[+|-]val[ymwdHMS]] ...
[-f fmt date | [[[[[cc]yy]mm]dd]HH]MM[.ss]] [+format]
expr: syntax error
[: -lt: unexpected operator
starting scrub of pool 'zdata':
cannot scrub 'zdata': pool is currently unavailable
consult 'zpool status zdata' for the result
usage: date [-jnRu] [-d dst] [-r seconds] [-t west] [-v[+|-]val[ymwdHMS]] ...
[-f fmt date | [[[[[cc]yy]mm]dd]HH]MM[.ss]] [+format]
expr: syntax error
[: -lt: unexpected operator
starting scrub of pool 'zroot':
cannot scrub 'zroot': pool is currently unavailable
consult 'zpool status zroot' for the result