disks for a small esx-host: ssd raid5 or hdd raid10?

Question

I am about to replace an ESXi host that runs some 20 VMs (mostly idling). Today around only 800Gb is used on an external iscsi-box, raid6 (total 7Tb).

The new server will just simply have internal disks. 2Tb will be plenty. It will most likely be a Dell R640 (max 8 discs). ESXi will be on a simple raid1 (2 small discs).

But the VM-storage? Which should i go for? (the HDDs are slightly cheaper, but no big diff).

A. 3 SSDs (960Gb) Raid5 = 2Tb

B. 6 HDDs (600Gb 10K) Raid10 = almost 2Tb

The server will have a dedicated raid-controller (perc) of course.

Does this answer your question? [Can you help me with my capacity planning?](https://serverfault.com/questions/384686/can-you-help-me-with-my-capacity-planning) — djdomi, Sep 29 '21 at 19:56
It looks like you are using OVH? Do you plan to use these drives as JBOD and configure the "RAID" as a ZFS raidz1 or whatever? — Michael Hampton, Sep 29 '21 at 23:28
Sorry dont know what OVH is. I'll let the perc (raid controller) handle the raid. — Alexander Kolodziej, Sep 30 '21 at 00:41
OVH is a provider of leased servers that operates mostly in EU and Canada. It would be very helpful to know who your provider is and exactly the specs of the server(s) you are looking at. — Michael Hampton, Sep 30 '21 at 05:52
sorry, dont know what leased servers or providers have to do with anything:) — Alexander Kolodziej, Sep 30 '21 at 11:36

score 2 · Accepted Answer · answered Sep 30 '21 at 11:10

RAID5 with SSD gives you much better performance on random I/O, approx. same redundancy level and scale-up slots. The suggested in comments configuration with cache makes no sense in my opinion, because it will cost more (or same) than SSD only storage, but it adds unnecessary complexity for storage and has lower performance.

You may find, that RAID5 is not recommended RAID level. It relates more to HDD drive, especially large capacity, because of two main reasons: slow random write performance; long and “potential risky” rebuild. SSDs works good in RAID5. Here more detailed description - https://www.starwindsoftware.com/blog/raid-5-was-great-until-high-capacity-hdds-came-into-play-but-ssds-restored-its-former-glory-2

Thanks, that settles it, going for raid5 with SSDs! – Alexander Kolodziej Sep 30 '21 at 11:39 — Alexander Kolodziej, Sep 30 '21 at 11:39

disks for a small esx-host: ssd raid5 or hdd raid10?

1 Answers1