Score:0

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

eg flag

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.

djdomi avatar
za flag
6x hdd and 2x ssd as cache would be IMHO the best option
djdomi avatar
za flag
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)
Michael Hampton avatar
cz flag
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?
Alexander Kolodziej avatar
eg flag
Sorry dont know what OVH is. I'll let the perc (raid controller) handle the raid.
Michael Hampton avatar
cz flag
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.
Alexander Kolodziej avatar
eg flag
sorry, dont know what leased servers or providers have to do with anything:)
Score:2
vn flag

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

Alexander Kolodziej avatar
eg flag
Thanks, that settles it, going for raid5 with SSDs!
mangohost

Post an answer

Most people don’t grasp that asking a lot of questions unlocks learning and improves interpersonal bonding. In Alison’s studies, for example, though people could accurately recall how many questions had been asked in their conversations, they didn’t intuit the link between questions and liking. Across four studies, in which participants were engaged in conversations themselves or read transcripts of others’ conversations, people tended not to realize that question asking would influence—or had influenced—the level of amity between the conversationalists.