vsan hybrid suggestion

[Punkgeek]

Hello,

I have a Marshal 2600ss-T15k with 6x600 GB SAS drives (15000RPM).

I am planning to configure VSAN on the dl360 g7 servers and I am looking for suggestions. The dl360 G7 has 10 disk slots.

I need a configuration for general usage since we have different types of customers, some requiring IOPS while others require read or write.

Which configuration would be the most reasonable option:

• 2x500 GB EVO 870 SSD as the cache
• 2x256 GB EVO 870 SSD
• 4x256 GB EVO 870 SSD
• 4x120 GB EVO 850 SSD

Since I have 6 SAS drives, I can create two VSAN groups with each group consisting of three SAS drives and two SSDs as cache. However, I would like to know which one is more reasonable between these configurations.

[Lukasz Zasko]

Hi,

I suggest to build 2 DG with 3 HDD and add 1 cache SSD. In hybrid configuration SSD drives uses 70% of capacity for Read cache and 30% for Write cache. I can propose first option - 2 SSD with 500GB for cache.

There is interesting article which explain DG: https://blogs.vmware.com/virtualblocks/2019/04/18/vsan-disk-groups/ 

[Duncan Epping]

You can only have 1 caching device per diskgroup. So that is something to take into consideration. I would recommend using the largest caching device you have available.

ALL supported Samsung Devices for vSAN are listed here: https://www.vmware.com/resources/compatibility/search.php?deviceCategory=ssd&details=1&vsan_type=vsanssd&ssd_partner=82&vsanrncomp=true&page=1&display_interval=10&sortColumn=Partner&sortOrder=Asc

Make sure that the caching and capacity devices are on the HCL! On top of that, the diskcontroller also needs to be on the HCL!

[Douglas Bowen]

2x500 (the first option) is the only recommendable solution, but I would try and stretch to 2x750GB if possible, as this is better for cache.

[TheBobkin]

, The correct answer here should be that none of the options you mentioned should be recommended as Samsung EVO 8XX drives are consumer-grade devices not intended for enterprise storage platforms and thus are not on the vSAN HCL.

 

if you want to knowingly use an unsupported configuration then do note that you are then taking personal responsibility for supporting it yourself.

[Punkgeek]

Hello,

Thank you for your response. Could you please give me the name of an enterprise SSD drive with the same or close price?

Regards,

[TheBobkin]

 a 500GB 870 EVO is ~€50 - I highly doubt you will get any enterprise SSD for that or close.

Have a look on vSAN HCL, maybe use filter for only lower performance tier but certified for Hybrid Cache-tier (assuming that is what you are doing here) and see what ones are low priced - IIRC Micron 5xxx series are generally on the more affordable side.