[Newbie] Expansion from 2x2Tb to 3x3tb on Ultra 4 - Help

[Xophile]

Hi!

I'm running out of space on my Ultra 4 and have a few questions:

1. I will probably go with 3x3TB WD Red disks (or can I safely use the 4TB ones even though they are not on the HCL?). What's the best procedure? Do a backup to one of the new 3Tb discs, install the other two 3Tb:s and then let the NAS create a 2x3Tb array and then copy back all my data and finally add the third hdd?
2. Is there an 8TB limit on the Ultra 4? I've read something about an 8Tb limit here somewhere...
3. Should I wait for a newer firmware form my Ultra 4? I've read something about errors in a new file system for OS6?
4. Do I benefit if I, at the same time as I'm expanding (and doind all the backup work etc etc) to go from OS4 to OS6?
5. How long must I wait before installing the second and third discs?

Anythings else (besides a valid backup), I need to think of before I start?

Thank you very much in advance!

Regards

[vandermerwe]

You really need a backup before you start anything and you need to have a backup plan for when you have added your 3rd disk.
The 4tb seagate NAS drive is on the hcl for the newer readynas units. Strictly you could be denied support, but Netgear would be really nasty if they did.
You can do it the way you have suggested:
1. Backup data
2. Update firmware to 4.2.25
3. Backup configuration
4. Either hot replace each 2 tb with a 3 tb allowing resync after each or power down, remove both 2tb disks, labelling them with slot number, put it the two 3 tb disks then factory default the unit ( this is probably best )
5. When the volume has built, install addons.
6. Restore config
7.Restore data
8 Add 3rd disk - you now don't have backup,other than the 2 original disks but this won't be a useful backup for long.

The 8tb limit is an incremental volume size limit from the last factory default.
I would not advise trying to install OS6

[fastfwd]

You have a 2x2TB array (2TB usable capacity) and you want to expand to 3x3TB (6TB usable capacity). There are a few options:

1. Perform an online expansion:
a. With the NAS powered ON, add a 3TB drive to the array. Wait for it to resync (it'll take a couple hours), reboot when it finishes. At that point, you'll have a 7TB array with 4TB usable.
b. With the NAS powered ON, pull one of the 2TB drives. Wait for the NAS to notice (probably only a minute or so), then put a 3TB drive in the same bay. Wait for it to resync, reboot when it finishes. At that point, you'll have an 8TB drive with 5TB usable.
c. Repeat the previous step for the final 2TB drive. When it's done, you'll have a 9TB array with 6TB usable.

Advantages: Easy. Doesn't require manual backup and restore of data, addons, and configuration. Data remains accessible throughout the process.
Disadvantages: Takes a long time. If something goes wrong, you don't have a backup. If you need a more than 10TB usable capacity in the future, you'll have to do a factory-default reset at that time.

2. Use one of your new drives as a temporary backup, do a factory-default reset with the other two new drives, restore from the backup, then add the backup drive to the array. This is what you proposed.

Advantages: None, really. Mostly just a lot of work for nothing.
Disadvantages: Backup/initialize/restore/add will take just about as long as the online expansion. Data is unavailable for most of that time. If something goes wrong at the last step (adding the final 3TB drive), you don't have a backup. If you need more than 11TB usable capacity in the future, you'll have to do a factory-default reset again at that time.

3. Buy a dedicated external backup drive like the 4TB Seagate Expansion Desktop. Backup to that drive, do a factory-default reset with all three of your new 3TB drives (along with, optionally, one of your old 2TB drives), restore from backup.

Advantages: You have a backup all through the process and afterward. If you don't include one of your old 2TB drives in the new array, those 2TB drives will be untouched -- if you need to revert to your old configuration, you can just power down the NAS, replace the 3x3TB drives with your old 2x2TB drives, and you'll be back to where you started. Faster than the other methods. No 8TB expansion limit -- you'll be starting with 6TB or 8TB usable capacity, so future expansion can go all the way up to 14TB or 16TB usable capacity (impossible to reach with currently-available drives).
Disadvantage: Data is unavailable during the process. Adds the cost of a backup drive.

4. Use one of your new drives as a temporary backup, do a factory-default reset with the other two new drives AND the old 2TB drives, restore from the backup, then perform an online expansion by replacing one of the 2TB drives with the last 3TB drive.

Advantages: You end up with an 8TB array (2TB + 3x3TB). No 8TB expansion limit -- you'll have started with 7TB usable capacity (2x2TB + 2x3TB), so future expansion can go all the way up to 15TB usable capacity (impossible to reach with currently-available drives).
Disadvantages: Will take a long time. Data is unavailable during most of the process. If something goes wrong during the last step, you don't have a backup.

If it were me, I'd probably do option #3... But that's only because my data is valuable enough to me that I'd want to have a backup during the process and also in the future. Your situation might be different.

[dsm1212]

I wouldn't be so negative about option 2. First the two original drives are raid1 so EITHER one has a good copy of your data should you need to recover. Rather than having no backup it's the one with the most backup copies! Second if you don't factory reset with the 3tb drives then you end up with a 2TB stripe and a 1TB stripe on the array. XRAID2 only supports two stripes so if you ever want to go to 4TB you'd have to factory reset to fully use the new drives. If you go with 4TB drives now the two stripes are probably moot because I don't know if we'll ever see support for larger. Personally I feel a lot safer setting aside the current drives so I'd be looking at option 2. If something happens to those new drives unforeseen I could always fall back to where I started. I do like (and have) the external backup drive idea. Not only is it good to have, but you can put all three new disks in when you init the system. Don't underestimate how long it takes to add a 3TB drive :-).

steve

steve

[fastfwd]

dsm1212 wrote:
I wouldn't be so negative about option 2. First the two original drives are raid1 so EITHER one has a good copy of your data should you need to recover.

Thanks for the correction, Steve. You're right. Xophile, please disregard that portion of my earlier comment.

dsm1212 wrote:
XRAID2 only supports two stripes so if you ever want to go to 4TB you'd have to factory reset to fully use the new drives.

I don't think that's true. My Pro 6 is loaded with a 2TB drive, two 3TB drives, and two 4TB drives, and it uses the full capacity of each drive:

Ch 1 : Seagate ST4000VN000-1H4168 [3726 GB] 3721 GB allocated
Ch 2 : Seagate ST2000DM001-9YN164 [1863 GB] 1858 GB allocated
Ch 3 : Seagate ST3000DM001-1CH166 [2794 GB] 2790 GB allocated
Ch 4 : Seagate ST3000DM001-1CH166 [2794 GB] 2790 GB allocated
Ch 5 : Seagate ST4000VN000-1H4168 [3726 GB] 3721 GB allocated

That's a 5x2TB RAID5 stripe, a 4x1TB RAID5 stripe, and a 2x1TB RAID1 stripe.

dsm1212 wrote:
Don't underestimate how long it takes to add a 3TB drive :-).

The data is still available during the process, so it's not a HUGE deal... But yeah, my "couple hours" estimate was probably way too low.

[StephenB]

I generally figure that it will take approximately 12 hours to add a 3 TB drive to the array. The time estimates reported in frontview and raidar are not reliable btw.

Also, xraid-2 will do more than 2 layers, I have also had three drive sizes in my pro-6 and still got full capacity. The key constraint is that it only creates new upper layers - which is why new drives have to be at least as big as the largest existing drive in the array.

Personally I would
(a) get a dedicated backup drive
(b) back up the NAS, and then use option (1).

You can install 4x3TB drives w/o hitting the expansion limit. Going to 4x4TB will require a factory reset, but there is no particular reason to be too concerned about that now (unless you are seeing a large increase in your storage needs in the short term).

[Xophile]

I honestly don't know how I can thank you guys for taking the time to answer me!

I just got a baby girl, I'll let you know in a week or so how I have proceeded.

Thanks again everyone!

[StephenB]

Congratulations on the little one!

[dsm1212]

Congrats, life changing! Plus, now you'll need more storage for all the video and photos!

On the xraid layers > 3. Sorry I could have sworn I read that wasn't supported but apparently it is. Good to know. Thanks!

steve

[Xophile]

I finally have a moment of peace here, the baby is sleeping. 🙂

Thanks for your kindness again!

A few quick ones:
1. Why don't you recommend OS6? I will probably need a factory reset anyway and I see some extensions I want are available for OS6 but not in OS4.

2. When I remove a disc from the unit, can I read the data through a regular PC somehow? I guess I need Linux or something like that. Just curious since I might use the current discs as "backup" in the upgrade process.

3. So you think the 4tb Seagate discs will be fine? My warranty for the Ultra 4 is already gone so that won't help me...

Thanks again everyone!

[vandermerwe]

OS 6 is unsupported on your unit, if you run into a problem Netgear will not help you (they do support after warranty expires, usually for a fee though)
If you want OS 6 I would suggest buying a new readynas.

You can usually read a disk from a raid 1 array with http://www.diskinternals.com/linux-reader/. I wouldn't place too much reliance on this method though, it's usually a last resort technique when conventional backups don't exist.
As I said in my first post, if you remove the 2 2tb disks with the nas off and label them by slot number, you can always reinsert these to the nas (while off) if something goes wrong, then power up. The volume will still be intact with your data. Do not remove or insert them with the nas powered on if you want to use this technique.

Personally I think the Seagate NAS drives are OK. This model number:
ST4000VN000

[mdgm-ntgr]

You can install mdadm and lvm2 on Linux and mount an array from a 4.2.x box on that.

If you maintain a good backup go ahead and try OS6. I would recommend running the latest 6.1.6 RC. I can supply an image to downgrade back to 4.2.x if you need it.

Users have found 4TB drives work fine for them.

[vandermerwe]

Presumably as Xophile currently has 2 disks he should be able to use linuxreader?

[mdgm-ntgr]

I guess so.

[Xophile]

Thanks again!

Mdgm: are you running OS6 on legacy hardware? Any issues?

I can wait until 6.1.6 goes final maybe?

[mdgm-ntgr]

I am, but I have new units so I don't very actively use my legacy system that runs OS6.

You could wait for the final 6.1.6 release if you like, but the current RC should already be pretty stable.

[vandermerwe]

You could also look at this thread for other users' experiences:

viewtopic.php?f=51&t=70133&hilit=os+6

[Xophile]

Vandermerwe:

Thanks, just found that thread! 🙂