cassandra-user mailing list archives

Site index · List index
Message view « Date » · « Thread »
Top « Date » · « Thread »
From Rob Coli <rc...@digg.com>
Subject Re: Backup Strategy
Date Fri, 12 Nov 2010 22:40:51 GMT
On 11/9/10 5:15 AM, Wayne wrote:
>We are trying to use snapshots etc. to back up the data
> but it is slow (hours) and slows down the entire node.

The snapshot process (as I understand it, and with the caveat that this 
is the code path without JNA available) first flushes all memtables 
(this can take a while, and can trigger minor compaction) and then does 
the following per SSTable :

a) flushes all memtables ()
b) fork process (this can take a while depending on heap size)
c) ln /path/to/SSTable-etc.db /path/to/snapshot

In general this process should not take "hours". Are you perhaps, in a 
case where you have a very large number of SSTable files in a dir and 
are not using JNA? I have seen snapshots lag in those circumstances, but 
those circumstances were usually pathological..

=Rob

Mime
View raw message