RAID Stripe Size and XFS block Size for Immutable Repository with Linux

[joaoferreira]

Hi all,

I'm trying to figure out the best configurations for a Linux Immutable Backup Repository, in terms of performance and less waste of space.

So we have a Dell server and a MD1400 enclosure with 14 TB disks that will have the Linux Immutable Repository.

When creating the RAID 6 on the server, I need to choose the Stripe Block Size which following the Default Veeam articles show be between 256 and 512 KB.

First doubts arise after reading an old blog article from VirtualtotheCore, saying that it depends on the job configuration.
In the V12 the storage optimization changed to the size of the block, and recommends not to use less than 1MB for object storage. I've also read some posts with @Gostev saying the most used option should be 1MB.

But in this old post, a reference also is made for the Compression Level and how this affects the block size you should choose on the RAID and also on XFS filesystem on Ubuntu Server.

For what I understood, the Optimal Recommend compression level is 50% so, if Veeam Storage Optimization is set to 1MB, Veeam will tell to write on the storage 512k instead of 1MB. Is this right ?

Imagine I want to configure all the jobs with this settings:

Compression: Optimal (Recommended)
Storage Optimization: 1MB

Which are the best configurations for RAID and XFS block size ?

Thank you all

[joaoferreira]

I've found this article https://bp.veeam.com/vbr/3_Build_struct ... block.html about this topic.

But honestly I'm a bit confused about the image presented there.

For what I understand, if I want to use backup jobs with 1MB of Storage Optimization I need to setup the Storage RAID with 256 KB and the XFS filesystem with 128KB right ? But this is the best setup for waste less storage since they will be aligned or also for performance ?

Another question related with RAID configuration is the Disk Cache. I've read in some articles that we should disabled it and leave the write-back on the controller ? Anyone have done this ?

Thank you in advance!

[joaoferreira]

Reading more carefully when using 1MB on Veeam Job the Storage will write 512KB, so the Storage RAID should be 128KB and Filesystem with 64KB ?

[joaoferreira]

Amazing forum, thank you all for your help!

[Mildur]

Hello João

I apologize that your question was not seen. We always try to answer every unanswered question from all customers. Unfortunately I didn't saw this question because it had already several comments by yourself.

Our most current recommendations for Linux hardened repositories can be found in Hannes blog post from this year. The blog post was especially written for hardened repositories. Please check the chapter "Basic server configuration":
https://www.veeam.com/blog/hardened-lin ... tices.html

To summarize it:
- Raid stripe size 128KB or 256KB if no recommendation by the server hardware vendor
- Filesystem: XFS block size 4096 bytes (https://helpcenter.veeam.com/docs/backu ... repository)
- Veeam backup files: keep the default of 1MB

Let me know if you have more questions. Hannes will be back next week and can provide additional information if required.

Best,
Fabian

[joaoferreira]

Thank you Fabian, i've followed this blog recommendations.