[Dovecot] Maintaining data integrity through proper power supplies (slightly referencing Best filesystem)

[Daniel L. Miller]

On 1/31/2011 3:00 PM, Ron Leach wrote:
>
> All we want to do is not lose emails.
>
> What does everyone else do?  Lose emails?
>
> regards, Ron

I've followed several of the filesystem threads here with interest - and 
tips & insight on improving performance are always exciting.  But I'm 
very confused with regards to some of the questions about data 
integrity.  Filesystem selection can be at least as serious a commitment 
as marriage - but if the goal is to avoid data loss due to power 
failure, it seems the solution to the problem is not having the problem 
in the first place.

I'm responsible for running a massive server farm (1 box) for an 
extraordinary number of users (at least 5 active accounts) so I may have 
a distorted view of reality.  But I will say the only time I've lost 
mail has been through OP error (at least since I left MS Exchange 
behind...shudder).  And since that idiot IT guy looks an awful like my 
mirror image...

I'm sure those OPs with larger budgets might have some hardware 
suggestions for reducing the chance of hardware failure leading to data 
loss (I mean, other than using good components, installed properly with 
oversized cooling - and possibly proactive upgrade/replacements prior to 
anticipated lifetime failure - how can you ELIMINATE the possibility of 
a CPU/controller/HD just deciding to blow up?)

My first exposure to the wonders of UPS's had nothing to do with keeping 
the system on while the lights were out.  Having moved from a location 
where the power was relatively stable, I came to a new city and it turns 
out power quality sucks - and so do the grounds.  I had constant 
failures, crashes, and general unstable behaviour from my PC.  As soon 
as I added a UPS (with line conditioning) - problems magically disappeared.

If you have a proper-sized UPS, combined with notification from the UPS 
to the servers to perform orderly shutdowns - including telling the 
application servers to shutdown prior to the storage servers, etc. - 
doesn't that render the (possibly more than theoretical) chances of data 
loss due to power interruption a moot point?

-- 
Daniel