Sas drives or SSD ?

MassiveJim · 29 Oct 2020 at 02:20

My business server is a Dell R720.
Main storage is currently handled with 4 x 300GB SAS drives in RAID 10.
Running out of space, so considering upgrading the drives.

Do I buy 4 x 600GB 15k SAS Drives at about £80/90 each or go for 2 x Samsung PM883 960GB in Raid1 at a cost of about £350 total ?

The array is used for general network storage on a 2 person network, there are shared excel files that are use regularly.

WWYD ?

Hellsmk2 · 29 Oct 2020 at 06:52

I'd always buy what fits your budget. Simple as that.

If you can afford ssd, then go down that route. I doubt there's much difference in price at this point.

MassiveJim · 29 Oct 2020 at 12:26

Hellsmk2 said:
I'd always buy what fits your budget. Simple as that.

If you can afford ssd, then go down that route. I doubt there's much difference in price at this point.

Cost is about the same but configuration will be different
4 x 600GB in RAID 10
or
2 x 960GB SSD in RAID 1

On Holiday · 29 Oct 2020 at 17:04

I'd go for the 2x SSDs in RAID 1. Performance will be about the same as 4x SAS in RAID 10 however you'll still have those drive-bays free for the future.

BongoHunter · 30 Oct 2020 at 11:12

I'd also go for the SSDs - I think they would offer more performance in the use case described.

Euphoria · 31 Oct 2020 at 13:52

SSD in RAID 1 so when one fails the second one fails shortly after?

4 x 600GB 15k SAS Drives vote for me! SSD is great but running them as a RAID 1 is a NO NO

BongoHunter · 31 Oct 2020 at 14:02

Euphoria said:
SSD in RAID 1 so when one fails the second one fails shortly after?

4 x 600GB 15k SAS Drives vote for me! SSD is great but running them as a RAID 1 is a NO NO

RAID 1 is mirror isn't it? Should be fine?

A stripe would be brave!

Minstadave · 31 Oct 2020 at 14:17

Euphoria said:
SSD in RAID 1 so when one fails the second one fails shortly after?

4 x 600GB 15k SAS Drives vote for me! SSD is great but running them as a RAID 1 is a NO NO

I wouldn't worry much about RAID1 SSDs for his use case provided he is keeping backups.

He could get 4 1TB consumer SSDs and run RAID10 for the same money as the PM883s.

BongoHunter · 31 Oct 2020 at 14:31

Probably worth sticking to drives with PLP just in case - not sure how common that is with consumer drives

MassiveJim · 31 Oct 2020 at 14:43

Minstadave said:
I wouldn't worry much about RAID1 SSDs for his use case provided he is keeping backups.

He could get 4 1TB consumer SSDs and run RAID10 for the same money as the PM883s.

Backups are regular and working. 99.9% of data is non critical anyway.

In fact I have just had a look at what is actually on the drive, and a better way of doing this would be to move some none-essential data on to a cheaper storage medium
I have around 120Gb of machine images
and around 150Gb of various MS and Apple OS image files

None of these need to be on expensive storage.
I already have everything backed up to a 12TB Ironwolf drive, perhaps I should get another large capacity NAS drive and keep that data on there instead, finanically at least it makes more sense.
currently have 2 x PM883 RAID1 servering as the main OS drive for Hyper-V and storage of VMs
4 x 300GB SAS as main network shared storage
1 x WD 8TB Gold as main backup drive for my home NAS (Backups up over the internet)
1 x 12TB Ironwolf, serving as main backup for all data on network, is VEAMM repository drive as well.

The issue is that every bay is full at present so adding additional storage might not be possible.
Is there way of adding internal storage to the R720 chassis ?

EsaT · 31 Oct 2020 at 22:15

BongoHunter said:
Probably worth sticking to drives with PLP just in case - not sure how common that is with consumer drives

Server should anyway have UPS.
And if not buying more normal drives would basically leave budget for UPS.
Firecuda 120 would have similar write endurance as PM883 and actually two years longer warranty.

Euphoria · 1 Nov 2020 at 19:57

BongoHunter said:
RAID 1 is mirror isn't it? Should be fine?

A stripe would be brave!

Yes its a mirror but since SSDS have a limited number of disk access and RAID 1 writing to both drives. You increase risk of them both going at the same time or close together because they run out of disk. If you go for disks its totally random which is far better than RAID 1 SSD.

In an enterprise environment I do not know anyone who runs RAID 1 SSD. If you run a NAS just make sure you are able to port the RAID config to another NAS if any hardware fails. Not all raid migrations are possible. More data = takes a lot longer

Cyber-Mav · 1 Nov 2020 at 21:09

Raid 1 is mirror so if one drive fizzles and drops out of the array then the other one carries in working and you can replace the dead drive with a new one and the mirror will copy over to new drive.

Raid 1 is raid 1 be it mechanical or ssd

Keeps backups though since if data is deleted from one drive it will also delete from the other.

Euphoria · 1 Nov 2020 at 21:14

Cyber-Mav said:
Raid 1 is mirror so if one drive fizzles and drops out of the array then the other one carries in working and you can replace the dead drive with a new one and the mirror will copy over to new drive.

Raid 1 is raid 1 be it mechanical or ssd

Keeps backups though since if data is deleted from one drive it will also delete from the other.

Yeah pretty useless right when two ssds hit their drive limit at the same time and drop off.

Cyber-Mav · 1 Nov 2020 at 21:23

As in write endurance limit?
Shouldn't hit that unless drives were not specced for the workload
Drives like the micron 5300max in 960gb form have 8 petabytes of write endurance. Pair those up in a mirror and you be good unless your using it for cctv footage i doubt you going to hit the wear limit within the warranty period of 5 years.

Semple · 1 Nov 2020 at 21:32

Cyber-Mav said:
As in write endurance limit?
Shouldn't hit that unless drives were not specced for the workload
Drives like the micron 5300max in 960gb form have 8 petabytes of write endurance. Pair those up in a mirror and you be good unless your using it for cctv footage i doubt you going to hit the wear limit within the warranty period of 5 years.

Ignoring whatever it is rated for, euphoria's point is that the failure case for both drives will likely be very close, unless one fails way short of the other. Ideally you would actually have one drive slightly older/used than the other.

You'll never find an enterprise storage array using SSDs or even mechanical HDDs in raid 1 for the main storage. Normally raid 1 is only used for the host os disks.

Cyber-Mav · 1 Nov 2020 at 21:58

You will also find enterprises dont run the disks till failure, they usually change them on a upgrade cycle e.g 3 or 5 years.
Iv seen many enterprises use raid 1 for the os disks and vm hosts. Raid 5 and 6 getting pointless due to rebuild time on large disks.
I know 2 business that use raid 1 ssd for database storage and need fast access to the database.
I even know businesses running raid 5 or 6 with 146gb drives for the os and vms.
Just use whats in your budget and needs.

Armageus · 1 Nov 2020 at 21:58

Euphoria said:
Yeah pretty useless right when two ssds hit their drive limit at the same time and drop off.

Except that's why you also buy a 3rd drive at some point as a cold spare, but then swap it in to provide a different failure point, retaining the other drive as a spare.

Even with hard drives it can be beneficial to swap in drives of different ages or from different batches. (Generally our storage arrays at work are 75% used drives and 25% brand new drives)

Cyber-Mav · 1 Nov 2020 at 22:09

Exactly as armageus said. Also iv seen new drives fail before old drives too. It really is a lottery

Semple · 2 Nov 2020 at 11:49

Cyber-Mav said:
You will also find enterprises dont run the disks till failure, they usually change them on a upgrade cycle e.g 3 or 5 years.

That's not true in most circumstances. It would be too costly to replace the drives every X years. I know in our enterprise storage arrays that we've designed the bigger spec'd solutions have a total of 560 HDDs. That's likely a 6 figure bill to replace them all, when majority of them will still be running absolutely fine after 3/5 years. So they only get replaced when they start showing signs of failure.

Armageus said:
Except that's why you also buy a 3rd drive at some point as a cold spare, but then swap it in to provide a different failure point, retaining the other drive as a spare.

Even with hard drives it can be beneficial to swap in drives of different ages or from different batches. (Generally our storage arrays at work are 75% used drives and 25% brand new drives)

Our arrays actually already have spares built in, so the active disks run in a raid 6 config, and as soon as one has signs of failure then one of the spares kicks in, and replacement drive is sent to the customer.

I don't know the specifics of how the factory build them - i.e. whether they pull HDDs from different batches to populate the array. They are all new disks from the factory though, and will have a spin up test and the software installed, and the raid will be parity initialised before being shipped off to the customer.