Databases snapshot in Vmware
most of databases such as SQL and Exchange mail servers , creates log files before they get committed to the Database.
If I understand VMware creates Delta file (Snapshot).
if I understand when the Delta file is created new SQL logs will be created in the Delta file .
Now when the Delta file(snapshot) gets deleted, will the logs be committed to the SQL/Exchange Database itself, or just to folder in SQL/Exchange servers then the SQL/Exchange engine will be responsible for committing them to the Database ?
I have been told that Databases are not recommended to be snapshotted by VMware, but I cannot confirm that.
Any clarifications ?
Thanks
If I understand VMware creates Delta file (Snapshot).
if I understand when the Delta file is created new SQL logs will be created in the Delta file .
Now when the Delta file(snapshot) gets deleted, will the logs be committed to the SQL/Exchange Database itself, or just to folder in SQL/Exchange servers then the SQL/Exchange engine will be responsible for committing them to the Database ?
I have been told that Databases are not recommended to be snapshotted by VMware, but I cannot confirm that.
Any clarifications ?
Thanks
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let 's say some Exchange or SQL logs are already queued up on the server and have not been committed yet, that's before the backup gets initiated.
When the backup starts,The backup App will quiesce the Client machine and send requests through VMware API to get a snapshot created by VMware.
the new logs from now on, will be written into the snapshot(Delta file). that SQL/Exchange does not understand
When the backup is finished, the backup App will send an API request to VMware to delete the Snapshot.
so when the Snapshot gets deleted at the end of the backup, are those uncommitted logs in the Delta file + uncommitted logs in SQL/Exchange server that were there before Backup started, will get committed by SQL/Exchange ?
Sorry the simple answer is no they don't get committed.
The only method that SQL or Exchange will be told to "flush" or "commit" the logs, if the Backup Application is Application Aware!
which has got nothing to do with the VMware Snapshot...
Why not try it out...on your SQL and Exchange Servers.....
Manually Take a Snapshot, Wait 60 seconds, Delete the snapshot....watch the logs, do they disappear - I can tell you no they dont!
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I do not have the lab set up for it yet..
However, it makes senses, at the end of the backup , that the backup application will tell VMware(via API) to write the logs that are in the delta file to the folder where SQL/Exchange keep the logs. This way Sql/Exchange will commit the logs to the database
However, it makes senses, at the end of the backup , that the backup application will tell VMware(via API) to write the logs that are in the delta file to the folder where SQL/Exchange keep the logs. This way Sql/Exchange will commit the logs to the database
I do not have the lab set up for it yet..
Okay.
However, it makes senses, at the end of the backup , that the backup application will tell VMware(via API) to write the logs that are in the delta file to the folder where SQL/Exchange keep the logs. This way Sql/Exchange will commit the logs to the database
If Enabled at Backup Time in the Job, and IF and ONLF IF the VMware Backup Applicaton is Application Aware!
Not ALL Backup Applications are Application Aware.
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Symantec NetBackup uses API to talk either to Vcenter and ESX host..
however I am not sure when it comes to Logs how are they processed...
Whether VMware just delete the snapshot(that contains most recent logs), and put them back with the logs that were in a folder of SQL/Exchange server , and will be committed by SQL/Exchange. It makes sense that way rather than VMware delete the most recent logs in the snapshot and commit them to sql/exchange database along with the logs that have not been committed before the backup started...
Andrew:
Let's say the Backup solution we use is VMware Application aware..
how will it process the SQL/Exchange logs when the back up is finished ?
however I am not sure when it comes to Logs how are they processed...
Whether VMware just delete the snapshot(that contains most recent logs), and put them back with the logs that were in a folder of SQL/Exchange server , and will be committed by SQL/Exchange. It makes sense that way rather than VMware delete the most recent logs in the snapshot and commit them to sql/exchange database along with the logs that have not been committed before the backup started...
Andrew:
Let's say the Backup solution we use is VMware Application aware..
how will it process the SQL/Exchange logs when the back up is finished ?
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Thank you
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When the backup starts,The backup App will quiesce the Client machine and send requests through VMware API to get a snapshot created by VMware.
the new logs from now on, will be written into the snapshot(Delta file). that SQL/Exchange does not understand
When the backup is finished, the backup App will send an API request to VMware to delete the Snapshot.
so when the Snapshot gets deleted at the end of the backup, are those uncommitted logs in the Delta file + uncommitted logs in SQL/Exchange server that were there before Backup started, will get committed by SQL/Exchange ?
can you put up a steps here how this can happen ?
Thank you Andrew.