diff options
| author | Sachin Pandit <spandit@redhat.com> | 2014-09-23 07:03:11 +0530 |
|---|---|---|
| committer | Vijay Bellur <vbellur@redhat.com> | 2014-09-23 10:23:56 -0700 |
| commit | 6ddfdde6fb8de21c46442b4b6b15d5b6b1eff4e4 (patch) | |
| tree | 7778aedd19c34c677ba16844e85595f3d7ff4fa0 /doc/admin-guide | |
| parent | 5136c938dddd909ad7a998afa643dc3dcaa6233d (diff) | |
doc/snapshot : admin guide updation.
Change-Id: I1980bc0984f941cd415fbc754495353f561155a8
BUG: 1145069
Signed-off-by: Sachin Pandit <spandit@redhat.com>
Reviewed-on: http://review.gluster.org/8817
Tested-by: Gluster Build System <jenkins@build.gluster.com>
Reviewed-by: Vijay Bellur <vbellur@redhat.com>
Diffstat (limited to 'doc/admin-guide')
| -rw-r--r-- | doc/admin-guide/en-US/markdown/admin_managing_snapshots.md | 36 |
1 files changed, 36 insertions, 0 deletions
diff --git a/doc/admin-guide/en-US/markdown/admin_managing_snapshots.md b/doc/admin-guide/en-US/markdown/admin_managing_snapshots.md index 5618a4d9cdb..93be39d94d5 100644 --- a/doc/admin-guide/en-US/markdown/admin_managing_snapshots.md +++ b/doc/admin-guide/en-US/markdown/admin_managing_snapshots.md @@ -14,11 +14,47 @@ pre-requisites: * Each brick should be on an independent thinly provisioned LVM. * Brick LVM should not contain any other data other than brick. * None of the brick should be on a thick LVM. +* gluster version should be 3.6 and above. Details of how to create thin volume can be found at the following link. https://access.redhat.com/documentation/en-US/Red_Hat_Enterprise_Linux/6/html/Logical_Volume_Manager_Administration/thinly_provisioned_volume_creation.html +Few features of snapshot are: +============================= + +**Crash Consistency** + +when a snapshot is taken at a particular point-in-time, it is made sure that +the taken snapshot is crash consistent. when the taken snapshot is restored, +then the data is identical as it was at the time of taking a snapshot. + + +**Online Snapshot** + +When the snapshot is being taken the file system and its associated data +continue to be available for the clients. + + +**Quorum Based** + +The quorum feature ensures that the volume is in good condition while the bricks +are down. Quorum is not met if any bricks are down in a n-way replication where +n <= 2. Quorum is met when m bricks are up, where m >= (n/2 + 1) where n is odd, +and m >= n/2 and first brick is up where n is even. snapshot creation fails +if quorum is not met. + + +**Barrier** + +During snapshot creation some of the fops are blocked to guarantee crash +consistency. There is a default time-out of 2 minutes, if snapshot creation +is not complete within that span then fops are unbarried. If unbarrier happens +before the snapshot creation is complete then the snapshot creation operation +fails. This to ensure that the snapshot is in a consistent state. + + + Snapshot Management ===================== |