Recovering files after a crash

[Al Plant]

Erik Norgaard wrote:
> Hi:
> 
> I woke op to a crash this morning after a powerfailure, and now dmesg 
> shows this:
> 
> WARNING: / was not properly dismounted
> GEOM_LABEL: Label ufsid/442f8ac1c0db9af2 removed.
> GEOM_LABEL: Label for provider ad6s1a is ufsid/442f8ac1c0db9af2.
> GEOM_LABEL: Label ufsid/442f8ac5a7fa5dda removed.
> GEOM_LABEL: Label for provider ad6s1d is ufsid/442f8ac5a7fa5dda.
> GEOM_LABEL: Label ufsid/442f8ac950b22b46 removed.
> GEOM_LABEL: Label for provider ad6s1e is ufsid/442f8ac950b22b46.
> GEOM_LABEL: Label ufsid/442f8ad3e5c88ab8 removed.
> GEOM_LABEL: Label for provider ad6s1f is ufsid/442f8ad3e5c88ab8.
> GEOM_LABEL: Label ufsid/442f8ad59f647596 removed.
> GEOM_LABEL: Label for provider ad6s1g is ufsid/442f8ad59f647596.
> GEOM_LABEL: Label ufsid/442f8ae2200a8064 removed.
> GEOM_LABEL: Label for provider ad6s1h is ufsid/442f8ae2200a8064.
> GEOM_LABEL: Label ufsid/442f8ac1c0db9af2 removed.
> GEOM_LABEL: Label ufsid/442f8ac5a7fa5dda removed.
> GEOM_LABEL: Label ufsid/442f8ac950b22b46 removed.
> GEOM_LABEL: Label ufsid/442f8ad3e5c88ab8 removed.
> GEOM_LABEL: Label ufsid/442f8ad59f647596 removed.
> GEOM_LABEL: Label ufsid/442f8ae2200a8064 removed.
> 
> The problem is that I have no idea which files were affected.
> 
> So, now some questions:
> 
> First, how do I determine which files were corrupted? And how do I 
> recover these files?
> 
> Second, / is mostly read-only, in fact, I can't think of any file on 
> that partition that should be modified at all: /tmp is on a separate 
> partition, I have source files on /usr/local rather than the default, in 
> fact, only root user files are modified during a normal day, but it's 
> been days since I logged in as root.
> 
> How do I protect read-only files from being corrupted in the first 
> place? I have tried mounting / read-only but that gave a load of other 
> problems.
> 
> Thanks, Erik
> 
> 
Aloha Eric,

I think those readings are normal. But anything on a dead server is 
cause for alarm. I have lost powersupplies and mobo's from power strikes.

If you have power failures often you can put the server (or desktop) on 
an extended UPSupply. Here on the island we have some power outages that 
last as long as 8 hours. (Earthquakes and wind storms).2 years ago I 
took  2 small UPS and hooked them to 2 stationary gelcell batteries 
(similar to car batteries), which allow my equipment of 4 servers to 
remain up and online for at least 10 hours.

~Al Plant - Honolulu, Hawaii -  Phone:  808-284-2740
   + http://hawaiidakine.com + http://freebsdinfo.org +
   + http://aloha50.net   - Supporting - FreeBSD 6.* - 7.* - 8.* +
   < email: noc at hdk5.net >
"All that's really worth doing is what we do for others."- Lewis Carrol