Bug#556610: mdadm: Improvement for MD checkarray CRON

[martin f krafft]

also sprach Filip Valder <valder at boukal.netdevelo.cz> [2010.09.06.1759 +0200]:
> Following line is much more better for scheduling "fixed random"
> checks of mdadm raid devices. Otherwise it's very painful for nodes
> connected in a distributed file system to run it each month on 1st
> Sunday at 00:57:
> 
> 0 57 * * * root [ -x /usr/share/mdadm/checkarray ] && [ $(date +\%d) -eq $[1+0x`cat /etc/hostname /etc/hosts /etc/network/interfaces | md5sum | cut -c 1-9`%28] ] && /usr/share/mdadm/checkarray --cron --all --quiet

Thank you for this report and the idea.

I have two immediate problems with it:

1. I chose Sunday specifically so as to not interrupt work (which
   may well be a false assumption anyway).

   However, the new --idle command line option will probably
   alleviate this anyway.

2. Your solution works, and it's exactly what the (useless)
   /usr/bin/hostid should do. I am a little sceptical about using
   a non-standard approach for this.

Anyway, I am leaving it open for comments and consideration.

-- 
 .''`.   martin f. krafft <madduck at d.o>      Related projects:
: :'  :  proud Debian developer               http://debiansystem.info
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