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conversion MA/VSA linux to FREL - why XFS mount in needed ?

  • 19 March 2021
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Userlevel 2
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Hi,

i have used the article to convert VSA/MA as FREL for vmware. in the documentation i don’t understand the need of creating a XFS mount for the FBR cache folder.

there is a difference on the performance when the FBR cache is in ext4 instead of XFS ?

regards,

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Best answer by Bart 19 March 2021, 21:38

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Userlevel 6
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I don’t think that this is a must, but keeping in mind that XFS is the standard in RHEL7+ (and Centos), it’s also a bit better for peformance,

 

8.1.2.1. XFS

XFS is a robust and highly scalable 64-bit file system. It is the default file system in Red Hat Enterprise Linux 7. XFS uses extent-based allocation, and features a number of allocation schemes, including pre-allocation and delayed allocation, both of which reduce fragmentation and aid performance. It also supports metadata journaling, which can facilitate crash recovery. XFS can be defragmented and enlarged while mounted and active, and Red Hat Enterprise Linux 7 supports several XFS-specific backup and restore utilities.

As of Red Hat Enterprise Linux 7.0 GA, XFS is supported to a maximum file system size of 500 TB, and a maximum file offset of 8 EB (sparse files). For details about administering XFS, see the Red Hat Enterprise Linux 7 Storage Administration Guide. For assistance tuning XFS for a specific purpose, see Section 8.4.7.1, “Tuning XFS”.

also: 

  • Compared to XFS, Ext4 handles less file sizes for example maximum supported size for Ext4 in RHEL 7 is 16TB compared to 500TB in XFS.
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I believe the word here is Scalability and Performance

https://access.redhat.com/documentation/en-us/red_hat_enterprise_linux/8/html-single/managing_file_systems/index

"XFS is a highly scalable, high-performance, robust, and mature 64-bit journaling file system that supports very large files and file systems on a single host."

Userlevel 7
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Hi @christophe 

Hopefully this RedHat article helps inform your decision:

https://access.redhat.com/articles/3129891

Another way to characterize this is that the Ext4 file system variants tend to perform better on systems that have limited I/O capability. Ext3 and Ext4 perform better on limited bandwidth (< 200MB/s) and up to ~1,000 IOPS capability. For anything with higher capability, XFS tends to be faster.

XFS also consumes about twice the CPU-per-metadata operation compared to Ext3 and Ext4, so if you have a CPU-bound workload with little concurrency, then the Ext3 or Ext4 variants will be faster.

In general, Ext3 or Ext4 is better if an application uses a single read/write thread and small files, while XFS shines when an application uses multiple read/write threads and bigger files.

 

Thanks,

Stuart

Userlevel 2
Badge +7

Hi @christophe 

Hopefully this RedHat article helps inform your decision:

https://access.redhat.com/articles/3129891

Another way to characterize this is that the Ext4 file system variants tend to perform better on systems that have limited I/O capability. Ext3 and Ext4 perform better on limited bandwidth (< 200MB/s) and up to ~1,000 IOPS capability. For anything with higher capability, XFS tends to be faster.

XFS also consumes about twice the CPU-per-metadata operation compared to Ext3 and Ext4, so if you have a CPU-bound workload with little concurrency, then the Ext3 or Ext4 variants will be faster.

In general, Ext3 or Ext4 is better if an application uses a single read/write thread and small files, while XFS shines when an application uses multiple read/write threads and bigger files.

 

Thanks,

Stuart

Hi Stuart,

thanks for the reply.

on a VSA/FRE server we have single read/write thread and small files (with the limitation of 10000 files and 10GB recommended, i also considere this is small files) so the XFS use is not an evidence on this server.

thanks 

christophe

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