El Martes, 26 de abril de 2016 00:08:49 Chris Murphy escribió:
> > [root@backups ~]# btrfs fi df /mnt/backup
> > Data, single: total=1.79TiB, used=1.78TiB
> > System, DUP: total=32.00MiB, used=240.00KiB
> > Metadata, DUP: total=17.00GiB, used=15.55GiB
> > GlobalReserve, single: total=512.00MiB, used=37.72MiB
>
> This is an awfully full filesystem. Since ancient times it's been
> considered best to avoid getting a file system even 95% full let alone
> 100% full.
Hummm... the problem is that in a big filesystem, 5% of space is very much
space... I will modify my scripts for leaving a percent of space instead of a
fixed size in bytes.
> Surely you've waited a good long while for it to try to start deleting
> things,
My backup script checks for the available space and deletes the oldest
snapshot when the free space is less than 100Gb.
What sould be the calculation that tells me I am nearly running out of space
and I need to remove the oldest snapshot? The answer of "df" is enoug or I
should do some calculation including data and metadata?
> > [root@backups ~]# cat /etc/fstab |grep backup
> > LABEL=disco_backup /mnt/backup btrfs noauto,compress=zlib,compress-
> > force=zlib,commit=60,noatime 0 0
>
> When I delete subvolumes, I see it takes up to the commit time for the
> delete transaction to be committed, and it can be longer than this by
> up to a minute before the btrfs-cleaner process starts to work on
> freeing up extents. It's probably unrelated to the problem, but what's
> the use case for choosing a commit time of 60?
The intention was to improve the speed. The wiki says the default is 30
seconcs and it prints a warning when the value is above 300 seconcs. Then I
thought 60 should be a good value for speeding up the writing. Do you think I
should use a lower value?
May be this?
btrfs fi usage /mnt/backup -b | awk '
{
if ($1 " " $2 == "Device size:") size=$3;
if ($1 " " $2 == "Device allocated:") alloc=$3;
}
END {
print alloc*100/size
}
'
> Also there are two
> compress mount options that conflict with each other, is this
> intentional?
I did not thought that compress and compress-force are incompatible... The
intention is to force it to compress the data for using lower disk space.
Compress-force should be enough?
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