Using gjournal + gmirror on 7.0-RELEASE-p1 (amd64) server

[Manolis Kiagias]

Ashish Shukla आशीष शुक्ल wrote:
> Hi list,
>
> I've two Intel Xeon dual core-based servers running 7.0-RELEASE-p1
> (amd64). Those servers are running a software raid-1 using
> geom_gmirror. Today, when I rebooted them twice with 'reboot' command,
> raid-1 running on both servers got degraded to 0% + filesystem check
> resulted in 4-5 lost non-critical files. Later I found out that
> 'reboot' is not a recommended way to reboot a system, and I should use
> 'shutdown -r now'.
>
> Anyways, I'm thinking to use gjournal (in addition to gmirror) on both
> servers to avoid such situation in future. I'm already using gjournal
> on my desktop (with no gmirror) running FreeBSD 7.0-RELEASE-p1
> (amd64), with no issues. So, I wanted to know if gjournal + gmirror
> combo is stable enough to be used on a servers.
>
> And, if I go for gjournal, since I've an existing filesystem, I've to
> create a separate gjournal slice, so is it okay to create that gjournal
> slice on a non-gmirror backed storage, hmm...?
>
> TIA
>   

You should keep in mind that the space required for the journal depends 
on the usage load and not the size of the data provider. In other words, 
if you are using the default 1Gb journal size on your desktop, it may 
not be enough for a busy server.

I've used gjournal+gmirror on a machine - not anything really heavy 
loaded, but it has given me no problems. I first created the journals, 
and the gmirror-ed the entire disk.  It works as you should expect. I 
have not tried creating the journal on a non-mirrored storage. I suppose 
this would work too, but I have no idea how safe it would be.