Replacing 4tb with 14tb drives expanding SHR1

[Phone Guy]

If I am going to replace 2x 4tb drives with 2x 14tb drives, then adding 2x addition 14tb drives in a 6 bay DS1621+ that currently has 4x 4tb drives (so end will be 2x 4tb and 4x 14tb) I need to replace 1 4tb drive at a time, let it resilver (or whatever the right term is), let that one finish, then add the 2nd 14tb (replacing another 4tb), let it finish, then add my 2x 14tb drives in the two empty bays, and expand the pool in storage master, right? or is that the wrong way?

Should I add the two 14tb in the empty bays first and expand the pool, then replace the two 4tbs with two 14tb (one at a time).

What is the correct method, and will either way be faster than another?

 

[Rusty]

Everything said is correct no matter what path you choose. But, just to be on the safe side, what array model are you running atm? SHR, SHR2 or some conventional type?

 

[marco]

Yes, only one drive at time.

If done with hot swap, better to disable the drive (the disk) before remove it. Then you can replace it, and then you must start the repair of the pool manually.

SHR should expand automatically after the repair (when replaced the second HD of the couple).

@Rusty he wrote SHR1 on the title

 

[fredbert]

Just to confirm the end goal is a single SHR-1 storage pool with six drives (2x 4TB + 4x 14TB)?

It's probably just me being ultra-cautious but, with drives getting bigger and bigger, the need to make big single arrays, to me, seems to be getting less and less but everyone has their own needs. There are more points for errors available that multiply with more drives.

If it were me I would consider losing 4TB of storage from the single six drive SHR-1 and have two arrays: 2x 4TB; 4x 14TB. If I had six 14TB I'd be thinking either two 3x 14TB SHR-1 or a single 6x 14TB SHR-2. It's dependent on what usage I have for the storage. If pure backup, and I have another copy/clone, then I may even use a Basic storage pool like I do for Mac Time Machine (which is a nice to have in my case).

The recovery time with large amounts of data isn't getting that much quicker in the home environment, so when a 50TB pool dies it will take ages to get back to normal ops.

Sincerely,
Captain Gloom

 

[Phone Guy]

Everything said is correct no matter what path you choose. But, just to be on the safe side, what array model are you running atm? SHR, SHR2 or some conventional type?

Its an SHR1 pool, currently four 4tb drives in a 6 bay ds1621+

Yes, only one drive at time.

If done with hot swap, better to disable the drive (the disk) before remove it. Then you can replace it, and then you must start the repair of the pool manually.

SHR should expand automatically after the repair (when replaced the second HD of the couple).

@Rusty he wrote SHR1 on the title

So in storage manager choose the drive and click deactivate drive before I remove it? then proceed with new drive installation and I suppose at that point it will see the new drive and rebuild the pool?

Just to confirm the end goal is a single SHR-1 storage pool with six drives (2x 4TB + 4x 14TB)?

It's probably just me being ultra-cautious but, with drives getting bigger and bigger, the need to make big single arrays, to me, seems to be getting less and less but everyone has their own needs. There are more points for errors available that multiply with more drives.

If it were me I would consider losing 4TB of storage from the single six drive SHR-1 and have two arrays: 2x 4TB; 4x 14TB. If I had six 14TB I'd be thinking either two 3x 14TB SHR-1 or a single 6x 14TB SHR-2. It's dependent on what usage I have for the storage. If pure backup, and I have another copy/clone, then I may even use a Basic storage pool like I do for Mac Time Machine (which is a nice to have in my case).

The recovery time with large amounts of data isn't getting that much quicker in the home environment, so when a 50TB pool dies it will take ages to get back to normal ops.

Sincerely,
Captain Gloom

Yes, the end goal is to have two 4tb and four 14tb in a single SHR1 pool/array. I was under the impression that was the whole idea of SHR1/2 over Raid5/6 was the ability to mix drive sizes and maximize storage capacity...?

So you suggest building 2 pools? one from the 2x 4tb (like a mirror of 1 drive to the other). And the other being a 4x 14tb SHR1 42tb? or no raid and just raw independent storage?


Besides the ability to mix drive sizes, is there any advantage to SHR1 over RAID5 ... ?

 

[marco]

So in storage manager choose the drive and click deactivate drive before I remove it? then proceed with new drive installation

Yes, I done this last week!

and I suppose at that point it will see the new drive and rebuild the pool?

No, it wait until you click Repair

Here the full procedure for every single disk (one at time).

1) Storage Manager > HDD/SSD > Select Disk > Locate Drive (to be sure is the right one)
2) Storage Manager > HDD/SSD > Select Disk > Action > Deactivate Drive (to proper unlink it)
3) Control Panel > Hardware & Power > General > Beep Control > Beep Off (to stop the beep)
4) Replace the HD
5) Storage Manager > Storage > Storage Pool > Repair
6) Wait the repairing procedure to finish before replace the next disk

 

[Phone Guy]

Here the full procedure for every single disk (one at time).

1) Storage Manager > HDD/SSD > Select Disk > Locate Drive (to be sure is the right one)
2) Storage Manager > HDD/SSD > Select Disk > Action > Deactivate Drive (to proper unlink it)
3) Control Panel > Hardware & Power > General > Beep Control > Beep Off (to stop the beep)
4) Replace the HD
5) Storage Manager > Storage > Storage Pool > Repair
6) Wait the repairing procedure to finish before replace the next disk

Thanks! I might start this process later today!
Just waiting to see what @fredbert reply will be.
I realize a 50tb pool is huge, but in the grand scheme of nas, enterprise, data centers, that has to be a small pool. I assumed these things handled issues like this (big multidrive pools) am I putting too much faith in this?

 

[marco]

Personally I think that one single pool is fine.
But of course you need always a full backup.

Just keep in mind, that if you have two drives damaged simultaneously on the same pool, you need to recreate it and restore all data from backup.

But that question was for @fredbert

 

[fredbert]

Yes, the end goal is to have two 4tb and four 14tb in a single SHR1 pool/array. I was under the impression that was the whole idea of SHR1/2 over Raid5/6 was the ability to mix drive sizes and maximize storage capacity...?

So you suggest building 2 pools? one from the 2x 4tb (like a mirror of 1 drive to the other). And the other being a 4x 14tb SHR1 42tb? or no raid and just raw independent storage?


Besides the ability to mix drive sizes, is there any advantage to SHR1 over RAID5 ... ?

Sure it’s possible to do what want and I’m sure many do it. The ability to grow an array by adding a pair of large drives is where SHR is better for most users vs the equivalent standard RAID.

For me my concern, if I was thinking about this, is fault tolerance. And this is just a gut feeling because it’s a non-issue until the array fails. But bigger drives have more blocks and therefore more chance that across a multi-drive array there will be multiple errors that would then result in a serious degradation. You only get one drive failure before losing it all.

This is a question I’ve asked myself and have no good answer. On my DS1520+ I have a 4x 8TB SHR-1. Plus a spare 8TB that I could either have cold on the shelf, installed as hot standby, active making the array SHR-2.

I’ve jumped between cold and hot standby. This way I have the option of: using a 4 bay if the NAS fails; adding it if needed as storage; making SHR-2 if that really is compelling.

I don’t know what’s best but the more parts the more chance of failure, I guess.

If you need 50TB now then you can. But if you don’t need it all now then you could hold off adding all in one go.

 

[noblemd]

If I am going to replace 2x 4tb drives with 2x 14tb drives, then adding 2x addition 14tb drives in a 6 bay DS1621+ that currently has 4x 4tb drives (so end will be 2x 4tb and 4x 14tb) I need to replace 1 4tb drive at a time, let it resilver (or whatever the right term is), let that one finish, then add the 2nd 14tb (replacing another 4tb), let it finish, then add my 2x 14tb drives in the two empty bays, and expand the pool in storage master, right? or is that the wrong way?

Should I add the two 14tb in the empty bays first and expand the pool, then replace the two 4tbs with two 14tb (one at a time).

What is the correct method, and will either way be faster than another?

I upgraded to 14TB (12.23 TB after volume creation) EXOS x16 drives in my DS1520+ SHR1 - you need at least 2 x 14TB before you can take full advantage of the 14TB size (see RAID Calculator pictures). Also it takes 2+ days each time you add drives (2 drives Step 1/2 and Step 2/2 3+ days). I now have 4x14TB drives in my 1520 and plan to add 1 more. My 1520+ acts as a backup NAS for my DS1621+ and DS1821+.

What I did (recommendation) was to add 2x 14TB at first then add 1 drive each succeeding time. The grow procedure worked flawlessly. FYI-BTW: you won't see the result of the Grow until completed.

RAID Calculator | Synology Inc.

4x 4TB and 1x14TB / 2x4TB + 1x14TB

4x4TB and 2x14TB

2x4TB and 2x14TB

What I did

 

[marco]

Thanks! I might start this process later today!

Let me know how it goes! Also note that the repairing procedure can take around 1 day.
On my case, after the repairing, it started also the data scrubbing procedure. So be patient.

 

[darkshippo]

To be safe. Why don’t you create another SHR1 pool using 2x14TB. The rsync/copy all the contents on the 4x4TB-array to the 2x14TB. Because you are putting massive stress on 4x4TB by adding a 14TB at a time. If one or two drives fail. Then all data is gone.

 

[marco]

I think it depends a lot on the type of data, and how many is important to be quickly back online on case of issue. And of course the backup is a must.

But if a user just want many data for video streaming, and he has a backup, then I think he can have a single pool with many space.

 

[Phone Guy]

Just wanted to update, since it was asked of me... I finally got around to installing a couple of the 14tb drives. I only installed 2 at the moment, as I liked the idea of adding to it as needed (@fredbert). I replaced the two 4tb drives one at a time, exactly as @marco suggested. It took about 1 day per drive, afterwards I had to expand the pool to get the full amount of space. But overall it was a painless process. Now I have a few extra drives, and may find new uses for them? or not? Maybe switch to SHR2? Only time will tell. I currently have 2 backups of my main nas, on 2 other nas's, and the one with the 14tb's currently has the most storage available, and I think my plan is to use it (a DS1621+) as a central backup for everything in the house (laptops, pcs, phones, nases, etc) so the main nas will have a backup and this one will be the "*****" backup

Many thanks to all who posted.

 

[noblemd]

Be aware to use different size drives in an SHR you have to create the drive array with the smaller size drives first then add the larger drives.

 

[Phone Guy]

Be aware to use different size drives in an SHR you have to create the drive array with the smaller size drives first then add the larger drives.

Honestly it never occurred to me, I just assumed thats how people would use it. Makes sense, start with a few 1tb or 2tb drives, then add in 4tb or 8tb or whatever... makes sense, but it never dawned on me people may try to go the other way? So you're saying (for example) two 14tb drives in SHR1 could not add two 4tb drives? it would have to be two 4tb SHR1 adding >4tb drives...?

 

[marco]

With SHR is possible to add any additional drive size. But if a drive get replaced, must be of the same size or bigger.

And of course the drive (included it size), must be on the compatibility list of the specific NAS.

 

[Phone Guy]

With SHR is possible to add any additional drive size. But if a drive get replaced, must be of the same size or bigger.

And of course the drive (included it size), must be on the compatibility list of the specific NAS.

So then someone could, in theory, add two 4tb to an SHR consisting of two or more 10tb (as an example) providing they had empty bays available.
Obviously I mean add, not replace.

 

[fredbert]

See here and follow the embedded links for the DSM 6 and 7 specific help pages for adding/expanding the array.

What is Synology Hybrid RAID (SHR)? - Synology Knowledge Center

Synology Knowledge Center provides you with answers to frequently asked questions, troubleshooting steps, software tutorials, and all the technical documentation you may need.

kb.synology.com

The general rule for SHR is...

Drive size:

• For SHR: The drive you want to add must be equal to or larger than the largest drive in the storage pool, or equal to any of the drives in the storage pool.
  For example: If an SHR storage pool is composed of three drives (2 TB, 1.5 TB, and 1 TB), we recommend the newly-added drive to be at least 2 TB for better capacity usage. You can also consider using 1.5 TB and 1 TB drives, but note that some capacity of the 2 TB drive will remain unused.

 

[marco]

So then someone could, in theory, add two 4tb to an SHR consisting of two or more 10tb (as an example) providing they had empty bays available.
Obviously I mean add, not replace.

If you add (and not replace), a couple of drives, then are fine and fully used. Is not required to be of same size or larger of current drives.