#1 2020-01-15 16:47:51

czmamo
Member
Registered: 2020-01-15
Posts: 2

Trial testing error

Good evening, I'm finding troubles testing the new Datacenter version.
I'm probably missing something even after reading PDF, readme and site, when I try to backup a VM in my Esxi 6.7 host nothing happens but the first three lines of a running task, no errors but only two lines stating:

Trial version allows backups and replicas during 6 h. after each reboot
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Removed /tmp/xsi dir     OK
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Unlocked backup          OK
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Removed PID              OK

This in the first 5 minutes after installing the trial. Normally with other versions (free and pro even trial) I get errors explaining something to look to but in this case nothing happens.

Is the destination of the backup required to be a deduplicated folder or can it be a normal VMFS disk mounted via iscsi (where is now happening the backup with xsifree) ?
Thanks in advance
Massimo

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#2 2020-01-15 18:56:38

admin
Administrator
Registered: 2017-04-21
Posts: 1,363

Re: Trial testing error

The error says

Trial version allows backups and replicas during 6 h. after each reboot

"After each reboot" is not the same as "after installation". Reboot your ESXi host to try the software.

(c)XSIBackup-DC is indeed much faster than (c)XSIBackup-Free or (c)XSIBackup-Pro and it also uses smaller block sizes. Given th fact that VMFS has a limit of around 130.000 inodes, it's not very recommendable to use VMFS as the target of deduplicated repositories, which is where --backup action will copy the data, so you should use some ext4 or XFS file system mounted over NFS to host deduplicated repositories. If you host them in VMFS you will most probably reach the inode limit and block your FS as soon as you perform some VM backups. It is nonetheless perfectly valid and recommendable to use the --replica action to some ESXi VMFS datastore.

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#3 2020-01-16 13:34:31

czmamo
Member
Registered: 2020-01-15
Posts: 2

Re: Trial testing error

admin wrote:

The error says

"After each reboot" is not the same as "after installation". Reboot your ESXi host to try the software.

I was, in fact, missing something from the documentation! big_smile Thanks for the clarification.

admin wrote:

... so you should use some ext4 or XFS file system mounted over NFS to host deduplicated repositories

This clears me other questions, I'll go try with a NFS share or this type of backup.
Thank you!

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#4 2020-01-16 16:21:06

admin
Administrator
Registered: 2017-04-21
Posts: 1,363

Re: Trial testing error

We try to offer as much detailed information as we can, a quick combined search in Google (xsibackup + some topic) will point you to the most relevant information. Let us know if you miss something important.

Deduplication breaks up data into little chunks. (c)XSIBackup-DC, as opposed to other solutions which use key/value DBs, makes use of the file system to store data chunks. We find this to be much more convenient, in fact a FS is indeed a key/value DB in many ways. Not only that, but it's optimized for speed and reliability, thus adding a layer on top of it to perform the same task is somehow redundant.

Depending on how much data you accumulate into a deduplicated repository, you can end up hosting many millions of data chunks. Thus, the most important facts to take on account when employing block level deduplication (--backup action) are: speed when searching a given block and the number of inodes, namely number of files and dirs you can host in a given FS.

VMFS is a FS which was designed to store a small number of huge files whereas other file systems were designed for a general purpose and some of them are optimized to host a big number of small files. Thus VMFS has a limit of around 130.000 inodes, more than enough to host virtual disks, but very few to host deduplicated repositories.

This wasn't such a big concern when using (c)XSITools (--backup-prog=Xsitools:z) in (c)XSIBackup-Pro, especially if using a block size of 50MB, as the 130.000 limit was still enough to host quite a few TB of real data. Nevertheless, when using a block size of 1MB (DC's default block size), this is indeed something to be concerned about.

Among the dozens of available FSs for NAS devices and Linux distros, ext4 and XFS are the ones that yield the best performance in speed and at the same time they can host millions of files and folders, thus they are your best bets when it comes to host (c)XSIBackup-DC's repositories.

Please, do note that you choose the tools you need to perform a given task based on their characteristics, not on their popularity or on their reputation. Many people like ZFS, and it can be a great choice when it comes to host some type of data in some given contexts, nonetheless it can become a terrible choice to host (c)XSITools repos.

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