Parallelize maas-wipe

[Joshua McClintock]

I was looking at this code and it looks like it just loops through each disk found and then runs the wipe.

https://github.com/maas/maas/blob/master/src/metadataserver/user_data/templates/snippets/maas_wipe.py

When you have a machine with 25 SSDs that don't support secure erase it takes forever (22 hours).

root@MAASMACHINE:~# tail -f /var/log/cloud-init-output.log
SG_IO: bad/missing sense data, sb[]: 72 05 20 00 00 00 00 10 02 06 00 00 c0 00 00 00 03 02 00 21 80 02 f8 21 00 00 00 00 00 00 00 00
SG_IO: bad/missing sense data, sb[]: 72 05 20 00 00 00 00 10 02 06 00 00 c0 00 00 00 03 02 00 21 80 02 f8 21 00 00 00 00 00 00 00 00
SG_IO: bad/missing sense data, sb[]: 72 05 20 00 00 00 00 10 02 06 00 00 c0 00 00 00 03 02 00 21 80 02 f8 21 00 00 00 00 00 00 00 00
SG_IO: bad/missing sense data, sb[]: 72 05 20 00 00 00 00 10 02 06 00 00 c0 00 00 00 03 02 00 21 80 02 f8 21 00 00 00 00 00 00 00 00
SG_IO: bad/missing sense data, sb[]: 72 05 20 00 00 00 00 10 02 06 00 00 c0 00 00 00 03 02 00 21 80 02 f8 21 00 00 00 00 00 00 00 00
SG_IO: bad/missing sense data, sb[]: 72 05 20 00 00 00 00 10 02 06 00 00 c0 00 00 00 03 02 00 21 80 02 f8 21 00 00 00 00 00 00 00 00
SG_IO: bad/missing sense data, sb[]: 70 00 05 00 00 00 00 0a 00 00 00 00 20 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00
sdb, sdc, sdd, sde, sdf, sdg, sdh, sdi, sdj, sdk, sdl, sdm, sdn, sdo, sdp, sdq, sdr, sds, sdt, sdu, sdv, sdw, sdx, sdy, sdz to be wiped.
sdb: drive does not support secure erase.
sdb: started zeroing.

[Joshua McClintock (jmcclintock1)]

Would it be possible to parallelize this?