Drive Size/Addition Question

[IndianaJoe1216]

I have been using UNRAID for about 9 months now and I absolutely love it. I have a Ryzen 1800X running on an ASUS Prime X370 Pro board. This board only has 8 SATA ports and I am using 6 of them. I have 4, 4TB Seagate Ironwolf drives. 1 drive is parity and 3 are array with a 1TB SSD Cache and a 1 TB SSHD cache. I want to add some more array storage but I only have 2 SATA ports left on my motherboard. I am looking at throwing on another 4TB Ironwolf but I am also looking for future expandability. This raises a couple of questions.


Will I need another parity drive? At what point would I not be able to successfully rebuild data because the parity isn't big enough.


Can/should I get a larger size Ironwolf say 6 or 8TB to expand my storage or will the different size drives cause an issue?


Can I add a SATA PCIe expansion card in the future to add more drives/storage? If so what brand/model do you guys recommend or have experience with?

[Squid]

44 minutes ago, IndianaJoe1216 said:

Can/should I get a larger size Ironwolf say 6 or 8TB to expand my storage or will the different size drives cause an issue?

The parity drive(s) must be as large or larger than the largest data disk.  So if you get an 8TB drive for parity, and then repurpose the existing 4tb parity drive to be a data drive instead, you've gained 4TB of storage.

 

[tdallen]

Hi -

 

Your parity drive, along with the rest of the healthy drives in your storage array, should be able to help you rebuild a failed disk of any size.  Wiki Reference.  2 parity drives would help you recover from 2 simultaneous disk failures.  A second parity drive is usually added when you have a lot of drives (and "a lot" is subjective).

 

The parity drive(s) need to be as large as, or larger than, the biggest data drive.  (They should also be as fast as, or faster than, the data drives).  So if you want to add a 6 or 8TB data drive you'll need to upgrade parity either first or at the same time .  Different size drives don't cause any issues provided the parity drive meets the size requirements.

 

LSI based PCIe SATA expansion cards are recommended these days, either the IBM M1015, Dell PERC H310, or the actual LSI branded cards like the LSI SAS9201-8i, etc.  Most SATA controllers wind up getting purchased on eBay, look for server pulls from reliable vendors.

Edited August 30, 2017 by tdallen

[SSD]

Options:

- You can add another up to 2 4T drives, giving you 24T of storage

- You can add a larger parity, for example an 8T drive. Your 4T parity drive can become a data disk, and you'd have 20T of space. Your next data drive can be an 8T drive. Providing up 28T of space. (Parity has to be as large or larger than the largest data drive in the array)

 

After you have no more slots, and need to add space, you can replace smaller drives with larger ones. Not a good deal if you are swapping out perfectly good drives, but it is a good option if the drives you are swapping are small, old or having issues. But swapping a 4T for an 8T would give you 4T more space, and a 4T drive to sell or do something else with.

 

Instead of swapping smaller for larger, you could add a new controller to give more ports. I would suggest an LSI SAS9201-8i (~$50 on eBay) if you have a PCIe 2.0, x4 or x8 slot. It would give you 8 more ports for up to 8 more drives. Continuing with 4Ts, that would give an additional 32T of space. If you upped parity to 8T, you could add an additional 64T. If you upped parity to 10T, you could add 80T. etc, etc. Of course case constraints come into play with adding 8 more drives. (Different topic - but very much recommend hot-swap style cages for all your drives, like the CSE-M35T-1B).

 

Next step IMO is buy an 8T drive. Seagate archives or WD Reds from external enclosures are the best deals (<$200). The 8T would only net your 4T in additional storage (the extra 4T is a one time sunk cost for larger parity), but would net you 4T as your parity becomes a data disk. And you'd be set up up to add an 8T data drive next time. The additional 12T of space might keep you for a while. When time comes and you need more, then go down the extra controller route or consider swapping out the 4T.

 

[IndianaJoe1216]

12 minutes ago, tdallen said:

Hi -

 

Your parity drive, along with the rest of the healthy drives in your storage array, should be able to help you rebuild a failed disk of any size.  Wiki Reference.  2 parity drives would help you recover from 2 simultaneous disk failures.  A second parity drive is usually added when you have a lot of drives (and "a lot" is subjective).

 

The parity drive(s) need to be as large as, or larger than, the biggest data drive.  (They should also be as fast as, or faster than, the data drives).  So if you want to add a 6 or 8TB data drive you'll need to upgrade parity either first or at the same time .  Different size drives don't cause any issues provided the parity drive meets the size requirements.

 

LSI based PCIe SATA expansion cards are recommended these days, either the IBM M1015, Dell PERC H310, or the actual LSI branded cards like the LSI SAS9201-8i, etc.  Most SATA controllers wind up getting purchased on eBay, look for server pulls from reliable vendors.

Awesome, Thanks! What I am thinking is I could purchase a new 6TB drive, use that as a parity and pull the 4TB drive that is currently my parity and use it in the array would that hurt anything?

[DanielCoffey]

I just bought an LSI SAS9201-8i. Be aware it will probably come with a half-height bracket and order a spare full height one if you need it for your particular case. Check the screw spacing too. This is the type you might need... http://www.ebay.co.uk/itm/282572654860

 

You will want SAS to 4xSATA forward breakout cables. I ordered these... https://www.scan.co.uk/products/startech-16-ft-50cm-serial-attached-scsi-sas-cable-sff-8087-to-4-x-latching-sata

 

The SAS cards will run pretty hot so benefit from fair airflow. If they have been sitting in a box or server for years (mine was 2011) you may wish to replace the thermal compound. The heatsinks are usually held on by nylon push pins which may have got brittle so take care.

 

If you are wanting to watercool them, there are some older Southbridge coolers that may be compatible as the hole-to-hole spacing is 47mm. I will be posting on how I will change the TIM shortly but the water block will have to wait till I spec my new machine.

[tdallen]

1 hour ago, IndianaJoe1216 said:

What I am thinking is I could purchase a new 6TB drive, use that as a parity and pull the 4TB drive that is currently my parity and use it in the array would that hurt anything?

That's exactly what most folks do when they need more storage, and are starting to add higher capacity drives to their system.  The thinking there is that the next data drive you buy in the future will be a 6TB drive to go along with your 6TB parity drive.  Conversely, it isn't worth getting a 6TB parity drive if you only ever plan on having 4TB data drives.

[SSD]

2 hours ago, IndianaJoe1216 said:

Awesome, Thanks! What I am thinking is I could purchase a new 6TB drive, use that as a parity and pull the 4TB drive that is currently my parity and use it in the array would that hurt anything?

 

6TB drives may be more expensive than the 8T drives I mentioned. Might want to check it out.  8T is the "sweet spot" on drive pricing right now.

 

People always underestimate their space needs when buying into unRAID.  

[IndianaJoe1216]

On 8/30/2017 at 11:50 AM, bjp999 said:

Options:

- You can add another up to 2 4T drives, giving you 24T of storage

- You can add a larger parity, for example an 8T drive. Your 4T parity drive can become a data disk, and you'd have 20T of space. Your next data drive can be an 8T drive. Providing up 28T of space. (Parity has to be as large or larger than the largest data drive in the array)

 

After you have no more slots, and need to add space, you can replace smaller drives with larger ones. Not a good deal if you are swapping out perfectly good drives, but it is a good option if the drives you are swapping are small, old or having issues. But swapping a 4T for an 8T would give you 4T more space, and a 4T drive to sell or do something else with.

 

Instead of swapping smaller for larger, you could add a new controller to give more ports. I would suggest an LSI SAS9201-8i (~$50 on eBay) if you have a PCIe 2.0, x4 or x8 slot. It would give you 8 more ports for up to 8 more drives. Continuing with 4Ts, that would give an additional 32T of space. If you upped parity to 8T, you could add an additional 64T. If you upped parity to 10T, you could add 80T. etc, etc. Of course case constraints come into play with adding 8 more drives. (Different topic - but very much recommend hot-swap style cages for all your drives, like the CSE-M35T-1B).

 

Next step IMO is buy an 8T drive. Seagate archives or WD Reds from external enclosures are the best deals (<$200). The 8T would only net your 4T in additional storage (the extra 4T is a one time sunk cost for larger parity), but would net you 4T as your parity becomes a data disk. And you'd be set up up to add an 8T data drive next time. The additional 12T of space might keep you for a while. When time comes and you need more, then go down the extra controller route or consider swapping out the 4T.

 

Thanks for all the info! I think I am going to pick up an 8TB IronWolf and and then pull the 4TB and add it to my array. The LSI controller info is super helpful as well. Case constraints aren't really an issue because my UNRAID server is running inside of a Cooler Master Cosmos 2 and there are 8 drive bays in the basement alone on that beast.

[IndianaJoe1216]

Thanks everyone for all the help this community is fantastic!

[jtown]

On 8/30/2017 at 3:06 PM, bjp999 said:

 

6TB drives may be more expensive than the 8T drives I mentioned. Might want to check it out.  8T is the "sweet spot" on drive pricing right now.

 

People always underestimate their space needs when buying into unRAID.  

 

Second. /scruffy

[jtown]

23 hours ago, IndianaJoe1216 said:

Thanks for all the info! I think I am going to pick up an 8TB IronWolf and and then pull the 4TB and add it to my array. The LSI controller info is super helpful as well. Case constraints aren't really an issue because my UNRAID server is running inside of a Cooler Master Cosmos 2 and there are 8 drive bays in the basement alone on that beast.

 

I started with 2tb drives because that was the biggest available at the time.  I only got six 4tb drives in the array before skipping to 8tb at around $300.  6tb drives were never a good price point.

 

Newegg regularly puts the Seagate 8tb Expansion drives on sale for $150.  Twice in August that I noticed.  I've got 2 on my desk going thru pre-shelling diagnostics right now.  I have ST8000AS0002, ST8000DM004, and WD80EZZX drives in my array.  Whichever's cheapest when I'm looking to buy.  None have given me any trouble.  Even used a shingled drive for parity until I got one of the WD drives.

 

I don't know that I'd go with the IronWolf, tho.  That's $100+ more than shelling an external.  Of the [literally] hundreds of hard drives that have passed thru my homes over the years, two (2) have failed in the warranty period.  Yeah, yeah, anecdotal evidence and whatnot.  But, with a savings of $100+ per drive, you'll quickly come out ahead even if one of the shelled drives dies in under 3 years.  Just run diagnostics before you shell the drive to make sure it's not DOA.

 

Three $150 externals = $450.  Three IronWolf drives = $780.  For the price of those IronWolf drives, you can purchase 2 more externals and shell them and still have change left over.

 

10tb drives are right out, tho.  More than double the price for a 25% gain in storage.

[IndianaJoe1216]

9 minutes ago, jtown said:

 

I started with 2tb drives because that was the biggest available at the time.  I only got six 4tb drives in the array before skipping to 8tb at around $300.  6tb drives were never a good price point.

 

Newegg regularly puts the Seagate 8tb Expansion drives on sale for $150.  Twice in August that I noticed.  I've got 2 on my desk going thru pre-shelling diagnostics right now.  I have ST8000AS0002, ST8000DM004, and WD80EZZX drives in my array.  Whichever's cheapest when I'm looking to buy.  None have given me any trouble.  Even used a shingled drive for parity until I got one of the WD drives.

 

I don't know that I'd go with the IronWolf, tho.  That's $100+ more than shelling an external.  Of the [literally] hundreds of hard drives that have passed thru my homes over the years, two (2) have failed in the warranty period.  Yeah, yeah, anecdotal evidence and whatnot.  But, with a savings of $100+ per drive, you'll quickly come out ahead even if one of the shelled drives dies in under 3 years.  Just run diagnostics before you shell the drive to make sure it's not DOA.

 

Three $150 externals = $450.  Three IronWolf drives = $780.  For the price of those IronWolf drives, you can purchase 2 more externals and shell them and still have change left over.

 

10tb drives are right out, tho.  More than double the price for a 25% gain in storage.

I have an affection for Seagate Drives because I have NEVER had one fail on me. I've got a 4TB from 2010 that was my main drive in my first PC build that is still going strong. I also have a a 1TB from 2006 that I shelled that is still cranking as well. I've never gotten that type of longevity out of other drives before and the Ironwolf are built for this type of stuff so I know they'll hold up.

[IndianaJoe1216]

New drive will be here tomorrow? Anything I should look out for when swapping parity drives out? Do I need to add the new one before pulling the old one? Is there a specific process there?

[SSD]

I have sort of an optimized method of adding a new parity that has the following advantages ...

- One parity build

- No drive rebuilds

- Recoverable in case of a failed disk during parity build

 

Let's see if I can find the post ...

 

Found it, and even made a few tweaks based on new unRAID features.

Good luck!

[tstor]

Some theoretical musings: I do not understand why a parity rebuild is needed, when replacing the parity drive by a larger one and changing the old one to a data drive.

 

Adding a zeroed drive to the array does not change parity. Theoretically it shouldn't matter at all, whether the new drive becomes the new parity drive or a new data drive. Of course the repurposed parity drive would then be full of garbage and not mountable from the point of view of a file system. However a simple format would be sufficient, it would not be necessary to pre-clear the drive. That way upgrades to a larger parity drive could be done without ever leaving the array vulnerable.

 

Can someone explain me, where the practical implementation kills my theory or where I might be wrong? Please note that I am only talking about single parity arrays here. With dual parity this does not even work in theory.

[SSD]

Upsizing parity involves either transferring the parity info from the old to the new parity drive, or rebuilding parity from the data drives. They are equivalent if you think about it. But when you're done the old parity is out of the array. You'd have to preclear it to add it to the array later.if that's the desire, which it often is.

 

My process above provides a way to add the old parity to the array before rebuilding parity onto the new disk, and this eliminates the need to preclear the old parity.