#1 2019-08-28 11:35:18

JohnSmith
Member
Registered: 2019-08-28
Posts: 2

includememory for backup?

Hi,

Im getting familiar with ESXi Free 6.7 and decided to use XSIBackup-Free. I would like to ask about the --snapshot=includememory parameter. Its available in the free version, but i can find the use for it.

Once the underlying vmdk file is copied to the backup location, all i can do to restore it is to copy it back and power on the VM (aka boot the OS again). So why is there an option to include memory, when i cant restore the running state of VM? I understand the use of saving memory while taking snapshots (like in webgui, or on other virt. solutions), but not while creating a backup with XSIbackup Free.

I have read your instruction about restoring [1] and snapshots principles on VMware [2], still cant understand whats the use for include memory on free version. Could someone elaborate?


[1] https://33hops.com/xsibackup-restore-vm … hines.html

"XSIBackup copies the .vmx and the .vmdk files "as they are" to their backup point, thus simply copying them back to their original location is enough to restore the contents of these files. "

[2] https://kb.vmware.com/s/article/1015180

"This option is selected by default. If this option is not selected, and quiescing is not selected, the snapshot will create files which are crash-consistent, which you can use to reboot the virtual machine."


For now i have decided to use --backup-type=running for now, because so far it works great even after "restoration" and low impact on running VM, but im concerned about SQL server consistency in the future. Currently Im running just a test server, not a production environment. Thank you in the advance.

Last edited by JohnSmith (2019-08-28 11:38:04)

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#2 2019-08-28 17:18:59

admin
Administrator
Registered: 2017-04-21
Posts: 1,002

Re: includememory for backup?

Well, you are mixing quite a few questions into one.

As stated the --snapshot=includememory option inlcudes the memory of the VM alonng with the snapshot. To learn how to revert a VM to a snapshot, please refer to VMWare documentation.

https://pubs.vmware.com/vsphere-50/inde … 304A8.html

If you just perform a plain backup, including memory in the backup snapshot is useless, depending on the --backup-prog that you use, saving memory along with the snapshot could be useful, like when employing Onediff, which will preserve an intermediate snapshot in between backups.

That option might be selected by default in some VMWare GUI, but it's not in XSIBackup, if you want to include memory you must explicitly state it by using the --snapshot=includememory option.

Quiescing is necessary when using database servers. This is to preserve DB server atomicity in transactions and to make sure that any I/O operation that is still pending at the moment to take the snapshot is completed before actually taking it, and also that any other subsequent request is stored in the snapshot complete. Otherwise some DB transaction could be truncated, leaving your DB in an inconsistent state.

This feature is not standard, every DB server (or some other kind of transactional system), is unique, thus quiescing will in turn depend on some additional service/s provided by the DB manufacturer. Configuring quiescing can become cumbersome or plainly impossible, should the DB manufacturer not have provided the required software.

The easiest way to work this problem around is to use the DB server's service start/stop commands, as they must necessarily implement a way to ensure atomicity when stopping it. In any case, if you can afford to stop your server for a minute a day, the simplest approach is to just perform a --backup-how=warm kind of backup. This will stop the server, take a snapshot and start it up again from a stopped state, amaking sure that any DB transactions present in the snapshot are consistent.

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#3 2019-08-29 13:20:29

JohnSmith
Member
Registered: 2019-08-28
Posts: 2

Re: includememory for backup?

I was already thinking about stopping the database service for a few minutes, its not a problem with our usage. Thanks for all the info, will keep that in mind. Thank you. smile This topic can be closed.

Last edited by JohnSmith (2019-08-29 13:21:04)

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