Comments on: MySQL Snapshot from a full disk. Tar over ssh

By: Toby

Toby — Wed, 29 Mar 2006 23:16:35 +0000

Don’t forget (GNU) tar has the -C (change directory) option for this purpose, so in your example you could write

cartman> tar -C /usr/local/mysql -cvf – data | ssh stan ‘sudo tar -C /usr/local/mysql -xf -’

By: Eric Bergen

Eric Bergen — Wed, 29 Mar 2006 03:46:16 +0000

GNU Tar has the -z and -j flag for optional gzipping/bzipping.

By: Chris Moore

Chris Moore — Wed, 29 Mar 2006 02:01:40 +0000

I’m always finding this one-line bash script useful:

echo some:set:of:data:in:one:line | while read LINE; do FIRST=`echo $LINE | cut -d: -f1`; SECOND=`echo $LINE | cut -d: -f2`; echo $SECOND $FIRST; done

This script will spit out “set some”.

The general usefulness is that you can parse input to this script, line for line. It’s pretty easy to parse out pieces in various ways and then use them for some command you need the values for. Combine this with some output and error handling/redirection and you can whip together some quick-n-dirty solutions

By: Luke Hollins

Luke Hollins — Tue, 28 Mar 2006 17:18:37 +0000

I have had some issues with rsync between differing systems but it’s generally OK. In situations where you’re paying by the bit it’s very useful. For stuff tar misses I am thinking for example on FreeBSD of file flags from chflags and ACLs from get/setfacl.

By: Sheeri

Sheeri — Tue, 28 Mar 2006 14:38:48 +0000

My trick is df -h and du -sh. Always figure out the size of what you’re tar’ing up!!! Blindly tar’ing and coming back to find the disk is full is not responsible sysadmining. If you have a script to backup like that, a few simple tests to make sure you won’t run out of space (using df and du) are in order.

As well, you can tar | gzip -c and that will zip the input as it comes in, as opposed to tar’ing and then gzip’ing. Unfortunately, bzip2 doesn’t have a feature like that, as it compresses better.

By: Eric Bergen

Eric Bergen — Mon, 27 Mar 2006 22:28:49 +0000

Which os specific flags are you talking about?

I have tried rync in the past. It has proved to be more difficult than tar over ssh due to version mis matches and crashing

By: Luke Hollins

Luke Hollins — Mon, 27 Mar 2006 18:47:04 +0000

Only drawback with tar is it drops OS-specific flags. Have you tried rsync for this? it can cut down on the traffic I use it to make remote backups to machines on slow links.