How to count number of snapshots in a chain?

[Chirag Katbamna]

Hello all,

 

I had run into the issue “Snapshot chain is too long” some time back and took a lot of work to get out of it (see my other thread on that). However it happened again!! I got out of the issue easier this time by migrating the vhd to another SR.

 

however, I would like to have active monitoring on this - but besides running cli command like below, I do not know how else I can get a count of snapshots in the chain of a vhd. These snapshots are hidden so not visible via GUI console.

 

usr/bin/vhd-util scan -f -a -p -c -m d2ff04e8-16b9-434a-b89e-c0e9b3efd830.vhd

 

A command like the above lists out the vhd and any chain snapshots.

has anyone setup any script or API call to count the chain length? I would like yo do this automatically daily and setup an alert email if the chain gets over 5 snapshots for example.

 

[Tobias Kreidl]

Try switching to Objects view in the Navigation pane in XenCenter and then expand the Snapshots group to see all available snapshots.

You can also run from the CLI "xe snapshot-list snapshot-of=VM-UUID" to get a list of snapshots for a particular VM.

 

-=Tobias

[Chirag Katbamna]

I wanted to count snapshots of volumes/vhd files as I do not do VM snapshots from console. 

 I ended up doing simple word count (wc -l) which counts line feeds but still works for my needs 

 

For example 

 /usr/bin/vhd-util scan -f -a -p -c -m d2ff04e8-16b9-434a-b89e-c0e9b3efd830.vhd |wc -l
2

 

where 2 is the output and count of snapshot chain (base parent plus current changes)

 

[Tobias Kreidl]

That woks,too! Make sure you only count lines that truly pertain to the snapshots (you can always add a "grep" before the word count).

 

-=Tobias

[Sergey Polyakov]

1.  Total snapshots in pool
xe snapshot-list | grep "uuid ( RO) " | wc -l


2. Count chain
SH=9f4fb42b-7423-4987-b94c-8e8611e19d1c  // ( root vdi-uuid)
x=-1
while [ -n "$SH" ]
do
echo $SH
  SH=`xe vdi-param-list uuid=$SH | grep "snapshots ( RO)" | awk '{print $4}'`
  x=$(( $x + 1 ))
done
echo $x

[Tobias Kreidl]

Look good!

 

-=Tobias

[Mark Syms]

You can also see the chains in the /var/log/SMlog file when a scan operation is performed on the SR (or shortly thereafter anyway when the garbage collection process runs)