Synology NAS RAID 10 question

[vogam7]

Hey LTT NAS enthusiasts. I'm considering purchasing a Synology NAS to set up RAID 10. Is there a way to specify in their software which drives RAID 1 mirrors and which ones RAID 0 stripes? Long story short, I have 6 drives, 3 from WD and 3 from Seagate, same capacity & specs . I want to ensure that mirror drives in a set aren't from the same vendor. If such a thing isn't possible via software, would alternating them while inserting into the bay do the trick? I'm a little worried that Synology might randomly pick drives for mirroring, and I'd end up with 2 drives from the same vendor purchased from the same batch, increasing the likelihood of 2 drive failure and RAID 10 non-recoverability. Apologies if someone has already answered this. I've searched for this info in various forums and the Synology manual but couldn't find an answer.. Thank you

[manikyath]

it's generally not recommended to mix different drive models in one RAID array, because even if the specs on paper are the same, they may have very different write behavior.

 

besides that, any reason why you dont use RAID6? that would let any two drives in the array conk out rather than just 'singles out of a pair'.

 

commentary aside, i found this bit on synology's website:

Quote

Synology RAID 10 uses the "Near" structure. RAID 1 array consists of two adjacent drives, and these RAID 1 arrays are combined into RAID 0.

 

so they'd make a RAID1 out of bay 1+2, and another RAID1 out of 3+4, and then stripe 12 + 34.

[DrMacintosh]

If you're mixing and matching drives. SHR is the only way. SHR2 allows for 2 drives to fail and offers the same storage as RAID 10 in a 4 bay NAS. In a 6 bay NAS, SHR2 gives you another drive of capacity, but you can still only loose 2 drives. 

 

https://www.synology.com/en-us/support/RAID_calculator?raid=SHR_2|RAID_10

[vogam7]

1 hour ago, manikyath said:

it's generally not recommended to mix different drive models in one RAID array, because even if the specs on paper are the same, they may have very different write behavior.

 

besides that, any reason why you dont use RAID6? that would let any two drives in the array conk out rather than just 'singles out of a pair'.

 

commentary aside, i found this bit on synology's website:

 

so they'd make a RAID1 out of bay 1+2, and another RAID1 out of 3+4, and then stripe 12 + 34.

 

42 minutes ago, DrMacintosh said:

If you're mixing and matching drives. SHR is the only way. SHR2 allows for 2 drives to fail and offers the same storage as RAID 10 in a 4 bay NAS. In a 6 bay NAS, SHR2 gives you another drive of capacity, but you can still only loose 2 drives. 

 

https://www.synology.com/en-us/support/RAID_calculator?raid=SHR_2|RAID_10

Thank you for your inputs. The reason I'd stay away from RAID 5/6 and SHR/SHR2 is that with each drive capacity at 22 TB, rebuild times would be way too long for my comfort level. I'd rather have a 6-drive RAID 10 with 1 hot spare, as RAID 10 allows for much quicker rebuilds.

 

Alright, since mixing different drive models in one RAID array is not recommended, I'd instead opt to purchase two sets of 3 Seagate drives at different times and/or from different resellers to minimize the chance of two or more drives failing at the same time if there was a bad batch. From what I understood from manikyath's reply, even though there is no software control to specify RAID 1 drive pair, there's still an option to populate drives into corresponding bays to ensure no RAID 1 is set up from the same batch of HDDs

[Jarsky]

2 hours ago, vogam7 said:

Hey LTT NAS enthusiasts. I'm considering purchasing a Synology NAS to set up RAID 10. Is there a way to specify in their software which drives RAID 1 mirrors and which ones RAID 0 stripes? Long story short, I have 6 drives, 3 from WD and 3 from Seagate, same capacity & specs . I want to ensure that mirror drives in a set aren't from the same vendor. If such a thing isn't possible via software, would alternating them while inserting into the bay do the trick? I'm a little worried that Synology might randomly pick drives for mirroring, and I'd end up with 2 drives from the same vendor purchased from the same batch, increasing the likelihood of 2 drive failure and RAID 10 non-recoverability. Apologies if someone has already answered this. I've searched for this info in various forums and the Synology manual but couldn't find an answer.. Thank you

 

 

When you run the Storage Creation Wizard; you choose which disks you want to add to the pool. 

You can't however choose the position in which you want them. 

 

With Synology RAID though DSM uses the Near structure; so it will use adjacent drives. 

Effectively if you have a 6 bay NAS, you want to put WD in Slots 1,2,3 and Seagate in Slots 4,5,6.

 

Keep in mind RAID10 will be in pairs. So it would be WD1-WD2 WD3-SG1 SG2-SG3

It would be a RAID01 that would be WD1-WD2-WD3 SG1-SG2-SG3

 

RAID10 = You can lose up to 3 disks, but only 1 per mirror

RAID01 = You can lose between 2-3 disks, depending on which disks fail (this config isn't supported in DSM)

 

RAID6 and SHR-2 would give you a 2 disk protection against ANY disks in the pool. 

It does so at the expense of some performance for parity calculations, but its negligible for most cases. 

 

 

[vogam7]

Jarsky, thank you for your reply. I like the idea of RAID 10, but wouldn't your recommendation of inserting WD in Slots 1,2,3 and Seagate in Slots 4,5,6 be contrary to the goal I'm trying to achieve? Let's say WD happens to produce a bad batch of HDDs that fail within 2 years. With your example, I may end up with an unrecoverable RAID 10 should the two disks in the first two bays fail. Would WD1-SG1*, WD2-SG2*, WD3-SG3*  be a bad idea to minimize the chance of more than one failure per mirror?

(*or the same drive model from a different batch) 

[Blue4130]

@vogam7 All of your worries would be mitigated by having a backup. You do have a backup, right?

[vogam7]

Blue4130, sure 

[Jarsky]

22 hours ago, vogam7 said:

Jarsky, thank you for your reply. I like the idea of RAID 10, but wouldn't your recommendation of inserting WD in Slots 1,2,3 and Seagate in Slots 4,5,6 be contrary to the goal I'm trying to achieve? Let's say WD happens to produce a bad batch of HDDs that fail within 2 years. With your example, I may end up with an unrecoverable RAID 10 should the two disks in the first two bays fail. Would WD1-SG1*, WD2-SG2*, WD3-SG3*  be a bad idea to minimize the chance of more than one failure per mirror?

(*or the same drive model from a different batch) 

sorry I mixed that up, thats the correct order I meant. So yeah stagger them.