device free space limit setting

[dormando]

komtanoo.pinpimai at livetext.com wrote:
> Hi,
> 
> I had set up mogilefs in a very bad practice -- 1 partition holding
> everything(OS + devX). I have many of these machines which will take
> sometime to migrate. Now, one of them is filled up by mogilefs:
> 
> colo3:/tmp# df -h
> Filesystem            Size  Used Avail Use% Mounted on
> /dev/sda3             228G  217G     0 100% /
> 
> It's not totally out of space, but df shows 100% and it makes me worry.
> 
> Is there any parameter I can set to prevent this, like setting a device to
> readonly if available space is less than 20G or 90% ?
> 

You running mogile as root?

If you're using ext2/ext3, you probably have that magic 5% reserved for 
root. A normal user on that machine shouldn't be able to write anymore. 
root will though Until you're out of disk.

MogileFS does check free space, but the value's currently hardcoded 
somewhere, and it's set to 100 megabytes if I recall correctly.

You could easily monitor disk utilization through the admin interfaces 
(worst case, a wrapper around mogadm!), and set the device to readonly 
or drain. However, you should probably go ahead and set that guy to 
readonly now and leave it that way... Go add a few more disks and let it 
even out or drain the device.

-Dormando