I need to create a set of commands for our AIX Sysadmins that will allow them to run scripts against an XIO array to refresh a snapshot on demand. They do not want me to re-map/mask the snapshot devices every time. They are fine with stopping the DB and unmounting the filesystems. They did just fine with TimeFinder on Vmax so I have no trust issues with giving them an account on the XIO. And before anyone suggests it, we are having issues getting Appsync running so I'm steering away from that. Since they're unix guys they want a command, not a GUI solution.
I am not a fan of RESTful API. I have plenty of other things to do and becoming a JSON programmer is not one of them. The documentation for RESTFUL is awful. The doc for XIO commands is awful. There are no cookbooks. There are no models.
I'm told I can "refresh" an existing snap but I can't find any XMS CLI (or RESTFUL API) commands to "refresh". Is this a single command? Is it an operand of a command? Is it a series of commands? I'm lost. Any help would be appreciated. Thanks.
If you are planning to build a script, the recommendation is to use RestAPI since we make sure that RestAPI is kept backward compatible going forward. There is no such guarantee for CLI.
In any case, you should be looking at ‘create snapshot and reassign’ command for the snapshot refresh operation. Snapshot refresh is a new feature that was added in XtremIO 4.0 release. You should reach out to your EMC account team to help understand how snapshot refresh works.
Itzikr's Blog is useless. No use cases. No commands. No examples. Just marketing crap. Why are there no decent models or examples showing how to do what should be a relatively simple process? Show me an example in GUI. Show me one in XMCLI. Show me an example using a shell script that doesn't need to jump through flaming hoops. None to be found. This is not TimeFinder.
Unfortunately the snapshot refresh is not working. I've tried the GUI, and CLI with the "reassign" option, and both methods fail to refresh the snap from the CG and tanks the command with repeatable errors when you decline to save the backup. It also insists on creating a newly randomly named snap that it remaps to the target host. I need to refresh the target volumes/snaps with a copy from the source CG on demand. I can't put randomly numbered snapshot names in a script and update it every time I run it. At this point support L2 and L3 have seen the issue and are working on it.
This has now been acknowledged by EMC as a bug and is supposed to be addressed in the upcoming 4.0.2 patch release. In the meantime the solution (using XMCLI) is to use the create-snapshot-and-reassign command WITHOUT the "no-backup" option, then do a shell-game rename of the current snapshot-set to "old", the new snap to "current", then delete the old volumes. It works for my purposes. Reply to this thread if you want a copy of the script posted.
Both of those are known issues and are scheduled to be fixed in the next service pack. More specifically, we are fixing the issue where the command fails when you decline to save the backup snapshot. You should not have this issue though if you are refreshing the snapshot from a consistency group.
We are also making the refresh process convenient by not relying on the randomly generated name of the snapshot.
The script is below. The original script was written by Scott H. (EMC). I jazzed it up a bit for my use. The basic idea is a shell game of snap, rename, delete old stuff. Reply if questions...
#25Nov2015 MDK.
# The settings below will need to be modified
#
# XMS_USER - Username on the XMS. Needs ssh key-auth configured
# XMS_HOST - Hostname/IP of the XMS
# XIO_CLUSTER - Cluster name within XMS (use "show-clusters" command to determine it)
# CG - Consistency Group to refresh FROM
# SNAPSET - Snapshot Set to refresh TO. Data in this SNAPSET will be overwritten!
i am a symcli guy myself so i am trying to translate what you are doing in the script to solutions enabler terminology ..so that that i understand that volume refresh works in XtremIO. In Timefinder/Snap i would simply create/activate my STD/VDEV pairing to give me my snapshot, later one if it needed to be re-freshed i would recreate/active. I am trying to understand why do we have to play this game with creating new snapshot , rename current to old and then rename new to current. I assume this does not change snapshot volume WWN and AIX does not need to be rescanned and all its hdisk/hdiskpower go nuts ?
dynamox
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Posted November 18th, 2015 10:00
Solutions Enabler is the gold standard, no arguing there. Itzikr's page does have an example, scroll all the way to the bottom of the linked page.