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RAID questions
Hi! I have an old server with PERC6 RAID controller.
I have read that PERC6 is not a very good RAID controller, so I will use softRAID (linux).
What do you recommend with what I've got?
4 2TB hard drives
or
4 480GB SSD drives
And, RAID 1, RAID 5 or RAID 10?
I will run Proxmox and use 1 VM with Windows, and some other linux VMs
Thanks!
Comments
If you want performance use the SSDs. If you need space use the HDDs.
Completely depends on how much disk space you intend to use really.. SSD's would obviously be a lot quicker.
The decisive question is: What will that system be used for? Without knowing that we can't offer a reasonable well founded answer.
How important is speed vs data redundancy to you?
I”d say SSD with raid1
Ok, answers:
It's not that Perc 6i is bad, it's just that you won't get the full speed of the drives from it...especially on SSD.
4 SSDs with RAID 1?
Yes tell you why.
1 - you won’t go full speed anyway if using raid10 but you will be ok with raid1 and don’t make your ssd die very quick and dumping your disk speed than normal sata
2- I believe the motherboard are old and come with 3gbps there is no point to do raid10 with raid1 will be Maximum speed w/r and iops
3- 2tb drive are seems old with low speed especially they are not enterprise drives if you trying to install windows will be bad!
4- raid 1 ssd will be amount of space available to use!
Why don't you just go with RAID-10 for the 4x SSDs?
And is your config
4x SSD OR 4x HDDor4x SSD *AND* 4x HDD? Confused.SATA Version is: SATA 2.6, 6.0 Gb/s (current: 1.5 Gb/s)
I read that in RAID 10, only 2 drives are being used. and 2 spares. Are the spares mirrored?
I mean, I can config any of those.
RAID 10 is essentially RAID 1 and RAID 0 combined. You have equal striping and mirroring.
Assuming your 4 drives (4 x 480GB SSD): A1, A2, B1, B2
On RAID10:
A1 and A2 will be mirrored (RAID 1), so you'll have 480GB from those (let's say A)
B1 and B2 will be mirrored (RAID 1), another 480GB from those (let's say
RAID10 will strip your data on top of A + B (RAID 0), so you'll have 960GB available (raw capacity).
If one drive A and one drive B dies you can recover your array by replacing the failed drives. If both drives A or B die you loose your whole array.
@key900
Uhm, the 1.5, 3.0, or 6.0 Gb/s are on the SATA end (between SATA controller and disk). So he can get more speed out of Raid depending on how the SATA controller is linked to the core. Typically that's via PCIe w/ 10 Gb/s or better).
You can regard Raid 10 as a Raid 0 that is mirrored. This (almost) gives the best of both, the speed of Raid 0 and the redundancy of Raid 1. But at a price in terms of using the disks less efficiently than with Raid 5 which however seems to not be an important point in your case.
As you also seem to not needs lots of space, Raid 10 over the 4 SSDs seems to be the best solution for your needs.
Side note: (Soft-)Raid 10 also comes all but free in terms of processor use.
why not use 2x SSDs and 2x HDDs then? pair them up into two raid1 arrays so you'd end up having 480GB with ssd speed and 2TB for larger data... best of both worlds.
put your main system and the windows VM on SSD. for the linux thingies you can simply add two (virtual) drives via proxmox, if you want to have the system on the ssd part and data on the hdd. be flexible about it ;-)
also if the perc6 comes with battery backed cache I'd probably use that for the hdd raid.
No raid. BSOD.
Real men always use no protection and shed manly tears later in boobs of a woman.
But I dont need that space. I think I can get a cheap NAS and mount them there.
I think this one is not, but I'll check.
^^This^^
Keep in mind that 480 GB SSDs should ideally only be formatted out to 350 GB or so. Because of the way SSDs work they both perform slower and fail earlier if they are routinely run close to full. The easiest way to insure you don't fill them up is to not format them to capacity in the first place.
RAID 6 would be a better choice for 4 identical drives. You have the same 960 GB (raw) capacity, but any two drives can fail without data loss.
PERC6 only supports SATA3 for SAS, for SATA drives you're going to be capped at SATA2. I don't recommend SSDs on a PERC6.
How are you connecting these drives? Going through the PERC6 anyhow? As I recall, it doesn't have a JBOD mode, so it won't be able to pass the "trim" commands through, which will hobble performance (after a while) and shorten the life of the SSDs. And you might as well use the hardware RAID, rather than software-RAID'ing several RAID-0'ed drives. The old 3Gbps PERC6 will likely bottleneck most SSDs as well. They might still make sense for an all-database system doing tons of random I/O, otherwise, I'd go with spinning rust (and 2TB is your maximum drive size). Go with RAID-10 if you need speed, only RAID-5 if you need maximum space with poorer performance.
really? oh f*ck.
Ok, thanks for the suggestion.
Maybe I'll change the RAID card to a newer one, so I can get sata3 on ssds
You need to go all the way up to the Rx30 generation to get RAID cards that pass trim commands through to the SSDs. You'll find much better deals on older, non-RAID SAS cards.
You can ignore the TRIM requirement if you just over provision your SSDs (even more than they already are). I OP by 15% and haven't had any issues (with the same SSDs running in production for over 4 years).
Hello,
I would go with the sata drives too, use the PERC6 RAID controller and build a RAID5.
Why ?
To be logic, you have an old server, use old drives.
Then why not setup a RAID10 because you loose space, i read you; space does not seem to be a priority but, once you will start to use the server, you'll fill it.
Even if it is not a good advice because backups must be stored on external device you could make some backups locally or you can use it to hold backups from other devices, this way you could use the benefit of RAID and disk space.
You are about to setup Proxmox, even if you probably don't think about it, space will allow you to run labs, test new operating systems, duplicate a vdisk and mount it or boot on it without touching the original one etc...
Greetings
Thanks for the suggestions!