RE: [linux-lvm] lvcreate --snapshot ---> file descriptor 7 left o pen?

[Lutz Reinegger t-systems com]

Thanks for your speedy reply, Donald. I've appreciated that.
I am really glad to see that we are not the only ones messing around with
LVM2 snapshots and MySQL backups.
:)

>>> The 'flush tables with read lock' only persists as long as the connection is active.
Yes, I agree.

>>> I don't think you'll be able to do that directly in ksh
We are using a ksh coprocess + a command line MySQL client to issue the "flush tables with read lock" command;
then the script loops until the MySQL "Key_blocks_not_flushed" parameter reaches 0.
Subsequently the snapshot is taken; after completing the snapshot the locks are released
and the coprocess including the MySQL session is terminated.
I really "hope" this works as well as your approach.

But speaking of perl:
I am seriously considering porting my ksh script to perl because I am having some
trouble reading data from the coprocess.
So far I haven't found a way to read and check the "Query OK, 0 rows affected (Z.XY sec)"
from the MySQL client within the ksh coprocess.
But I am getting a bit of topic now...

Bye
Lutz