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Kimsufi 3 disks vs 2 disks (RAID)
Hi,
On a Kimsufi server with 3 x 480 GB SSD, is it possible to set up a RAID 5, and if so, will the available space be roughly 900 GB or am I saying BS?
In that case, from a disk point of view, isn't it better to have 3 x 480 GB in RAID 5 than a 2 x 960 GB in RAID 1 ?
Thank you,
Comments
960GB drives have higher TBW and generally RAID1 is better due to being less computationally harder (if we are talking about software RAID)
When having more drives, RAID1 is much more reliable, however RAID5 has higher writing performance and more storage is available.
Only you decide what is actually better for your case.
Thank you @FlorinMarian and @tentor, this confirms what I was thinking.
Well, sometimes.
On a 3-disk system, I would provision both ways, run I/O tests, and see whether I prefer RAID-1 or a RAID-5. The parity computations during writes can negate the benefit multi-disk writing. Not sure about your requirements, but if you're not compiling/building code or something that benefits from fast I/O, then RAID-5 would be my recommendation to get more space and good fault tolerance.
One more option is RAID-1 across 3 drives. A little known option and big waste of space, but extra redundancy.
Personally, I would always pick a RAID-1 or RAID-10 setup over a RAID-5 or RAID-6. I want the best I/O.
Yes, this is what I've been doing so far, because I didn't know what to do of a third drives
Well in both cases you can only lose one drive, so there's no extra redundancy with RAID5. The only thing it gives is lessens the probability of having an issue with the setup. Like it was mentioned before 960GB drives have better durability, so my Kimsufi choice would be RAID1 hands down.
Thank you @Crab for sharing your opinion.
raid5 is economical.
However, there is a penalty for write speeds, not for reads. So it totally depends on what you want to get out of it.
If there is no difference in price, raid1's 960G should be more balanced in every way.
If you want RAID 5 to be as safe as RAID 1 in case of power failure, you have to pay a fairly significant write penalty by enabling PPL
For a RAID 5 on SSDs in a datacenter, I'd take the risk and go with no PPL or bitmap
Thank you @danblaze and @darkimmortal for your comments.