yum with recent soas builds on XO-1

Mikus Grinbergs mikus at bga.com
Thu Aug 13 13:28:25 EDT 2009

>> Apparently irrespective of the content of /etc/fstab, recent
>> F11-on-XO1 builds are _mounting_ /var/cache/yum as a tmpfs.
> After a very quick look, F11-on-XO mounts tmpfs there only via
> /etc/fstab, so I don't know how to explain this.  If you find
> the answer I'd be interested to know it.

I don't know the answer.  One experience I had on SoaS3 was that 
with /etc/fstab *not* containing an entry for /var/cache/yum, 
'mount' showed /var/cache/yum mounted on tmpfs.  I issued 'umount 
/var/cache/yum' which appeared to execute normally.  [IIRC, I was 
thereupon able to run 'yum', since it now used space in the root 
filesystem for its cache.]  Much later, I used 'yum' again - and it 
failed - because the /var/cache/yum was *again* mounted on tmpfs (I 
don't know why or how) and ran out of room.

>> I do not know how come yum on SoaS3 tries to stuff that additional
>> huge file into /var/cache/yum, when os5 does not -- but tmpfs on my
>> XO-1 is *definitely* not big enough.
> SoaS3 puts this mount in /etc/fstab _and_ runs
> /etc/init.d/livesys{,-late}, which mount tmpfs there.

Because I'm unable to myself convert .iso to .img, I'm forced to run 
(boot) SoaS3 from an USB stick.  After SoaS3 has been running for a 
while, /etc/fstab does *not* contain any entry for /var/cache/yum.

In fact, with soas builds, I've not seen any changes to /etc/fstab 
(except for the ones I myself put there).  And as far as I can 
remember, soas builds initially put only five entries in /etc/fstab 
[when I look at the mounted /dev/dm-something filesystem (which 
should be the unchanged filesystem as created from the .iso), it 
definitely has only five entries in /etc/fstab].

For illustration, here are outputs taken [in Terminal, once Sugar 
came up] after booting strawberry (from USB):

> 0 [liveuser]# mount
> /dev/mapper/live-rw on / type ext3 (rw,noatime)
> proc on /proc type proc (rw)
> sysfs on /sys type sysfs (rw)
> devpts on /dev/pts type devpts (rw,gid=5,mode=620)
> tmpfs on /dev/shm type tmpfs (rw)
> none on /proc/sys/fs/binfmt_misc type binfmt_misc (rw)
> /dev/sda1 on /mnt/live type vfat (rw)
> varcacheyum on /var/cache/yum type tmpfs (rw,mode=0755)
> /tmp on /tmp type tmpfs (rw)
> vartmp on /var/tmp type tmpfs (rw)
> /dev/dm-1 on /media/Soas2-2009062213 type ext3 (ro,nosuid,nodev,uhelper=devkit)
> 0 [liveuser]# cat /etc/fstab
> /dev/root  /         ext3    defaults,noatime 0 0
> devpts     /dev/pts  devpts  gid=5,mode=620   0 0
> tmpfs      /dev/shm  tmpfs   defaults         0 0
> proc       /proc     proc    defaults         0 0
> sysfs      /sys      sysfs   defaults         0 0
> /dev/mmcblk0p1 /media/1e54e244-34b0-4f46-9f49-9616fba60282 ext2 defaults,noatime 0 0
> /dev/mmcblk0p2 none  swap    sw               0 0
> 0 [liveuser]# df
> Filesystem           1K-blocks      Used Available Use% Mounted on
> /dev/mapper/live-rw    2064208   1415200    628080  70% /
> tmpfs                   110432        76    110356   1% /dev/shm
> /dev/sda1              7816232   1207572   6608660  16% /mnt/live
> varcacheyum             110432         0    110432   0% /var/cache/yum
> /tmp                    110432        20    110412   1% /tmp
> vartmp                  110432         0    110432   0% /var/tmp
> /dev/dm-1              1204716   1204716         0 100% /media/Soas2-2009062213
> 0 [liveuser]#

The first five entries are what strawberry put into my /etc/fstab. 
I manually added the last two.  The additional tmpfs "mounts" appear 
to have taken place __without__ entries for them being present in 
/etc/fstab.  (Note:  with SD cards, sometimes the boot-time 
automount gets bypassed, as in this example.  Usually, 'mount' (and 
'df') would have shown the /dev/mmcblk0p1 filesystem as well.)


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