Poor performance VSAN Vsphere

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CedricT
Posts: 36
Joined: Mon Apr 15, 2019 1:14 pm

Thu Mar 25, 2021 9:40 am

Hi,

We have this configuration:

2 HPE DL385Gen10
Raid Controler: HPE RAID Smart Array P408i-a SR Gen10
10 HDD 1.2To SAS 10k => RAID 5 (not the best option we know)
1 SSD 1.7 To => RDM for cache L2
1 SSD 1.7 To => RDM for cache L2

We noticed we have a very poor performance if we disable the cache on the RAID 5 even if we use cache L1 starwind

Is there any trick with this raid controler?

Thanks
yaroslav (staff)
Staff
Posts: 2279
Joined: Mon Nov 18, 2019 11:11 am

Thu Mar 25, 2021 11:11 am

For HDDs, please always use RAID controller cache.
CedricT
Posts: 36
Joined: Mon Apr 15, 2019 1:14 pm

Thu Mar 25, 2021 11:27 am

Since i was following this recommandation i don't clearly understand

https://knowledgebase.starwindsoftware. ... ssd-disks/

Recommended settings for hardware RAID arrays based on HDD:

RAID type: RAID 10

Disk cache policy: Default (disabled by default)

Write policy: Write Back

Read policy: Read ahead

Stripe Size: 64K
yaroslav (staff)
Staff
Posts: 2279
Joined: Mon Nov 18, 2019 11:11 am

Thu Mar 25, 2021 12:05 pm

In your original post, you reported bad performance with RAID 5 cache disabled. I mentioned that you need to enable it (in our KB you can see that we recommend write-back cache), disk caching is a bit different thing.
CedricT
Posts: 36
Joined: Mon Apr 15, 2019 1:14 pm

Fri Mar 26, 2021 9:38 am

Alright my bad!

Clearly we misread the recommandations.

Thank you again!
yaroslav (staff)
Staff
Posts: 2279
Joined: Mon Nov 18, 2019 11:11 am

Fri Mar 26, 2021 9:55 am

No worries, always glad to help you!
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