Return-Path: Delivered-To: apmail-cassandra-user-archive@www.apache.org Received: (qmail 56250 invoked from network); 8 Mar 2011 09:26:27 -0000 Received: from hermes.apache.org (HELO mail.apache.org) (140.211.11.3) by minotaur.apache.org with SMTP; 8 Mar 2011 09:26:27 -0000 Received: (qmail 37768 invoked by uid 500); 8 Mar 2011 09:26:24 -0000 Delivered-To: apmail-cassandra-user-archive@cassandra.apache.org Received: (qmail 37695 invoked by uid 500); 8 Mar 2011 09:26:24 -0000 Mailing-List: contact user-help@cassandra.apache.org; run by ezmlm Precedence: bulk List-Help: List-Unsubscribe: List-Post: List-Id: Reply-To: user@cassandra.apache.org Delivered-To: mailing list user@cassandra.apache.org Received: (qmail 37687 invoked by uid 99); 8 Mar 2011 09:26:24 -0000 Received: from athena.apache.org (HELO athena.apache.org) (140.211.11.136) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 08 Mar 2011 09:26:24 +0000 X-ASF-Spam-Status: No, hits=1.5 required=5.0 tests=HTML_MESSAGE,RCVD_IN_DNSWL_LOW,SPF_PASS X-Spam-Check-By: apache.org Received-SPF: pass (athena.apache.org: domain of sylvain@datastax.com designates 209.85.161.172 as permitted sender) Received: from [209.85.161.172] (HELO mail-gx0-f172.google.com) (209.85.161.172) by apache.org (qpsmtpd/0.29) with ESMTP; Tue, 08 Mar 2011 09:26:18 +0000 Received: by gxk5 with SMTP id 5so2509322gxk.31 for ; Tue, 08 Mar 2011 01:25:57 -0800 (PST) MIME-Version: 1.0 Received: by 10.236.63.209 with SMTP id a57mr1295196yhd.11.1299576356952; Tue, 08 Mar 2011 01:25:56 -0800 (PST) Received: by 10.147.34.2 with HTTP; Tue, 8 Mar 2011 01:25:56 -0800 (PST) X-Originating-IP: [88.183.33.171] In-Reply-To: <5FAFCB6230A1754CBC58296E62D8D5E602E89EECD7@pa-ex-01.YOJOE.local> References: <5FAFCB6230A1754CBC58296E62D8D5E602E89EECD7@pa-ex-01.YOJOE.local> Date: Tue, 8 Mar 2011 10:25:56 +0100 Message-ID: Subject: Re: when do snapshots go away? From: Sylvain Lebresne To: user@cassandra.apache.org Cc: Jeffrey Wang Content-Type: multipart/alternative; boundary=485b39067a4d1d61fb049df53329 --485b39067a4d1d61fb049df53329 Content-Type: text/plain; charset=ISO-8859-1 On Tue, Mar 8, 2011 at 1:53 AM, Jeffrey Wang wrote: > Hi all, > > > > When I drop a column family, it creates a snapshot. When does the snapshot > go away and free up the disk space? I was able to run nodetool clearsnapshot > to get rid of them, but will they go away themselves? (Also, is there a > purpose to keeping a snapshot around?) > No, they won't go away by themselves. Using nodetool clearsnapshot or manual deletion are the correct way to get rid of those. The purpose of the snapshot is to protect yourself against mistakes. Moreover, unless you are doing tests, it's almost always good practice to keep a backup of whatever you drop, just in case you realize later on that there was some data you needed to keep, so this also take care of that for you. And it's far easier for you to know what to do with the snapshot (whether that is deleting it or archiving it somewhere) than for the application. -- Sylvain --485b39067a4d1d61fb049df53329 Content-Type: text/html; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On Tue, Mar 8, 2011 at 1:53 AM, Jeffrey Wang <jwang@palantir.com> wrote:
=

Hi all,
=A0
When I = drop a column family, it creates a snapshot. When does the snapshot go away= and free up the disk space? I was able to run nodetool clearsnapshot to ge= t rid of them, but will they go away themselves? (Also, is there a purpose = to keeping a snapshot around?)

No, they won't go away by = themselves. Using nodetool clearsnapshot or manual deletion are the correct= way to get rid of those.=A0

The purpose of the sn= apshot is to protect yourself against mistakes. Moreover, unless you are do= ing tests, it's almost always good practice to keep a backup of whateve= r you drop, just in case you realize later on that there was some data you = needed to keep, so this also take care of that for you. And it's far ea= sier for you to know what to do with the snapshot (whether that is deleting= it or archiving it somewhere) than for the application.

Sylvain

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