Re: Why is there a time difference between snapshot names and snapshot times?

jensn · ‎2010-09-16

The following setup show a difference of 2 hours between the scheduled time - which is included in the snapshot name - and the timestamp on the snapshot as shown on the storage systems.

Primary controller with timezone Europe/Copenhagen

Secondary controller with timezone Europe/Copenhagen

Both controllers uses ntp service, syncing against the same timesource.

The DFM server is running on a windows server with timezone GMT+1

The time is currently in summertime or daylight saving time.

Protection Manager is supposed to do local backup of a fileservice volume and the snapvault this to a second site.

The backup schedule is for testing purpose setup with 15 min intervals. The ide is to do local backups and the replicate every 15 min.

We can see from the backupname which has the time as Protection Manager enterprits it and the actual timestamp from the storage systems differs with 2 hours.

When we changed the time on the DFM server with 2 hours the name and the timestamp got into sync, but this cannot be the right way to setup a backup system.

What timezone should be configured on the backup server for this to work correctly?

mheimberg · ‎2010-09-16

We can see from the backupname which has the time as Protection Manager enterprits it and the actual timestamp from the storage systems differs with 2 hours.

By the wisdom of software engineering some developpers decided to use only GMT in the snapshot-name timestamps, regardless of the timezone set in the system.

So with your timezone GMT+1 plus daylight savings these are exactly the 2hrs difference....you have to get used to it

Mark

smoot · ‎2010-09-16

Don't get too used to it. In the next release we'll format the timestamps to match the dataset's local time.

mheimberg · ‎2010-09-16

These are good news.

Do you also get rid of the disturbing blanks in the snapshot names?

And will there be underscores or dots (like in other SnapManagers) as time-separator instead of colons? Or at least the SDU-naming convention (underscores) the default?

regards

Mark

adaikkap · ‎2010-09-16

yes we are also getting rid of spaces.For the time being you can turn the below option on.

[root@lnx ~]# dfm options list pmUseSDUCompatibleSnapshotNames
Option Value
------------------------------- ------------------------------
pmUseSDUCompatibleSnapshotNames No
[root@lnx ~]#

Regards

adai

mheimberg · ‎2010-09-16

Dear Adai

yes we are also getting rid of spaces.

These too are good news!

For the time being you can turn the below option on.

[root@lnx ~]# dfm options list pmUseSDUCompatibleSnapshotNames
Option Value
------------------------------- ------------------------------
pmUseSDUCompatibleSnapshotNames No

IMHO this option should be by default set to YES - because: when it is set to no (actual default) it uses colons in the time stamp (8:35:47), and with those it is no longer possible to access the previous versions from Windows Explorer on the primary storage system -> you are taking away one of the coolest features of NetApp snapshot=the self service restore of files.

Once again this snapshot name discussion shows the weakness in NetApps development organization: obviously the particular teams don't talk to each other, so every group is establishing its own naming convention, and NetApp also seems to miss to establish internal guidelines concerning the most important feature of their platform - I have no other explanation for what I observe in SnapManager for Oracle, SME/SMSQL, DFM, SMVI, it's simply a mess.

regards

Mark

adaikkap · ‎2010-09-16

NMC shows the time in the local time of the server on which its is running.

But snapshot names in the filer have GMT time stamp.

Regards

adai