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Showing posts from May, 2017

Backups, Snapshots and Arrays, oh my!

There seems to be some confusion about what qualifies as backups and what doesn't. I'd like to take a minute to clear this up.

Backup: According the Merriam-Webster.com, a backup would be defined as "a copy of computer data"... emphasis on the word "copy"

First, let me cover what snapshots are in almost every system that uses them. A snapshot goes through certain steps:
1) Snapshot is requested
2) System (be it virtualization system, OS or array henceforth referred to collectively as "system") quiesces the data to commit any buffered data
3) Data is locked by the system (now referred to as source)
4) Change log is created (referred to a "new data")
5) As data changes are requested, pointers are created that reference the source with the new data updated. As more data is updated, the change log can grow up to the size of the original source data
6a) New snapshot (multiple snapshot config): change log is frozen like the original source data and n…

NetBackup Virtualization Resource Limits

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Alright everyone, I wanted to share another little gem that isn't really well known in NetBackup:
Resource Limits

This is available for both VMware and Hyper-V, and allows you to limit backups based on various options to prevent you from thrashing your virtualization farms. Sorry Xen, you're still not supported yet. You get to it from Host Properties -> Master Server -> Properties -> Resource Limit

First, let's look at the options available for the 800-lbs gorilla in the room, VMware:

vCenter, snapshot, Cluster, ESXserver, VMXDatastore, Datastore, DatastoreFolder, DatastoreType, VMXDatastoreNFSHost, DatastoreNFSHost and DatastoreCluster. Sounds promising right?

Let's go down the list:
vCenter - Maximum jobs that can run per vCenter - good if you have a small vCenter Server
snapshot - Maximum snapshot creates/deletes that can run at the same time - will not limit backups, only snapshot operations
Cluster - Limits jobs running on a vSphere Cluster
ESXserver - Limits …

NetBackup VMware Backups - to SWAP or not to SWAP

In our configuration of NetBackup, we came across the option to "Exclude swapping and paging files" when performing VMware Backups. This sounds good right? Less to backup (making backup windows smaller) as it'd all be recreated on reboot anyways?

Caveat emptor!

First, excluding the swap doesn't exclude the files, merely the data within.

Second, depending on your version, if you have multiple swap files configured in Windows, it may only exclude the first and not the remaining, per article:
https://www.veritas.com/support/en_US/article.000025484

Third, and what I find to be the most critical, when backing up Linux VMs with this option enabled (which I think it is by default), upon restore the /swap partition isn't created and/or the swap is disabled. This will require you to manually re-enable or recreate the swap partition. This is stated in the following knowledge base article:
https://www.veritas.com/support/en_US/article.000023097

Conclusion:
Unless you are backing…

3rd Party VADP Backup selection criteria

As a Backup Administrator, I try to look for ways to more efficiently manage my time and resources, as well as automating what I can. In our environment we have 3 big name backup solutions that we support due to various reasons, and many of our clients use dedicated backup agents on the boxes.

VMware based backups that were done used manual VM selection criteria due to various reasons. To me, this seemed a bit wasteful. When my VMware Admin approached me informing me of a plan to migrate some hosts and upgrade VMware I figured this was a good time to approach the idea of automating the VM selection method.

We sat down and looked at our 3 backup software solutions to find what we could use. Names, Tags, Datastores, Folders. As we looked we realized that while all our solutions supported VADP to some extent, some support some methods, some would have to be upgraded to support methods and some wouldn't support other methods. As a spoiler, Tags, while nice, was the least supported met…