Upgrade to Ultra 4 Plus, Max storage capacity

Steve 46 wrote:
1. If I were to load up the Ultra 4 Plus with four 2TB HDD's and use the X-RAID configuration for redundant backup, what is going to be my maximum actual storage capacity? I'm assuming it is going to be 4TB but wanted to confirm.

For the default single drive failure protection you would get 6 TB of available storage, not 4. If you went with protection against two drive failures you would get 4 TB. It is best not to think about this as "backup" - you should still have an independent backup.

Steve 46 wrote:
2. I am going to backup all data and remove the two HDD's I have in the Ultra 2 Plus and install these drives into the Ultra 4 Plus to start. During the initial setup of the Ultra 4 Plus will it need to re-format the drives thereby erasing all data or is there a way to set up the X-RAID without erasing the data on the HDD's?

Since they are both in the same family, you should be able to simply more the drives over with no problem. You should make a backup first though.

However, there is a benefit to doing a factory default/drive wipe with all four HDDs installed. There is an 8 TB ceiling on expansion. So if you start with 2 TB available storage, you won't be able to expand beyond 10 TB. However, if you factory default with all the drives installed, you will start with 6 TB of available storage, allowing expanstion up to 14 TB.

Steve 46 wrote:
3. Regarding future expansion, when I am ready to add two more HDD's to the Ultra 4 Plus do they have to be the exact same model of Hitachi HDD's?

No.

Steve 46 wrote:
4. Finally can someone offer any thoughts on the "Link Aggregation" feature using the two ethernet ports. Does this improve performance in a home use environment? Any other thoughts or tips relating to upgrading to a higher capacity NAS are appreciated.

Link aggregation is only applicable on the Pro line, as it is a business feature. So you will not get it on an ultra plus. It won't improve performance for a single user, though there is an improvement if you have multiple devices accessing the NAS at the same time. It is nice to have, but in my view the main reasons for home users to consider the Pro is the generally faster CPUs and the longer warranty.

X-RAID2 on 2-bay and 4-bay ReadyNAS is the single-redundancy variant. The dual-redundant option is available on the 6-bay systems, but there is the option to use Flex-RAID RAID-10 on 4-bay systems.

3. Be sure to choose disks from the Hard Disk HCL. NetGear can and will deny support if you use drives outside this list. You can use multiple different drive models in the NAS.

4. As mentioned by StephenB. Link Aggregation is only available on the Pro line. Even if it was on the Ultra models you'd be unlikely to see much (if any) of a performance benefit anyway (with the exception of the Ultra 6 Plus). For a performance benefit from teaming you need to choose a mode that provides a performance benefit and have multiple client machines accessing the NAS simultaneously and using different protocols. It is possible to install a community add-on to enable Teaming on the Ultra/Ultra Plus models but this is unsupported. I use it and find it works for me on the Ultra 6 but this is not for the average user.

Thank you for the informational replies. Stephen B, If I am understanding you correctly (regarding max expansion capacity to 14TB) if I load up all four 2TB drives now and do a drive wipe I will get 6TB capacity with the ability to remove those four 2TB drives and replace them with a combination of larger drives totaling 14TB (without having to do another factory default/wipe). Is that correct? If that is the case then I will most likely just buy two more drives and install all four now to maximize storage capacity. I would be good to go for a while with 6TB available space.

Regarding X-RAID, I understand that is the default single drive failure protection configuration. So if I have four drives loaded and one fails I would still retain all my data? I also understand that one drive is for parity information but not really understanding how one drive can protect the information on the three other drives. What if the parity drive fails?

All comments on Link Aggregation are noted. Just wanted to make sure if it was something I should be utilizing. I may have been asking about the wrong feature though. I was wondering why the Ultra 2/4 Plus units have two ethernet ports.

Thank you,

Steve 46 wrote:
Thank you for the informational replies. Stephen B, If I am understanding you correctly (regarding max expansion capacity to 14TB) if I load up all four 2TB drives now and do a drive wipe I will get 6TB capacity with the ability to remove those four 2TB drives and replace them with a combination of larger drives totaling 14TB (without having to do another factory default/wipe). Is that correct?

That's correct. Of course you'd remove one drive at a time then add a higher capacity disk, wait for resync etc. to complete before replacing next disk.

Steve 46 wrote:
Regarding X-RAID, I understand that is the default single drive failure protection configuration. So if I have four drives loaded and one fails I would still retain all my data? I also understand that one drive is for parity information but not really understanding how one drive can protect the information on the three other drives. What if the parity drive fails?

X-RAID uses a dedicated parity disk (with four disks this is effectively RAID-4). However you have X-RAID2 which has distributed parity. X-RAID2 with four equally sized disks is like RAID-5.

Think of it like this:

A = 1/3 B + 1/3 C + 1/3 D
B = 1/3 A + 1/3 C + 1/3 D
C = 1/3 A + 1/3 B + 1/3 D
D = 1/3 A + 1/3 B + 1/3 C

If any one disk fails data remains intact because the data on the failed disk is spread amongst the other disks. Now the same principles apply as you start to add higher capacity disks.

With say 2x2TB + 2x3TB

You would have an additional RAID-1 layer of 2x1TB on the 3TB disks. Remember an X-RAID2 array can only expand when redundant space can be added so if all drive bays are full with disks of equal size you need two higher capacity disks.

Have a look at X-RAID2 in Action (though this animation is for the 6-bay models the same principles apply on the four-bay models and the 2-bay models).

Steve 46 wrote:
I may have been asking about the wrong feature though. I was wondering why the Ultra 2/4 Plus units have two ethernet ports.

Very similar to the Pro Series devices hardware wise. Ultra 2 Plus and Pro 2 have same hardware, Ultra 4 Plus and Pro 4 have same hardware. You can use the two NICs to connect to two networks or for manual failover. You can even make two connections to the same network.

Steve 46 wrote:
Regarding X-RAID, I understand that is the default single drive failure protection configuration. So if I have four drives loaded and one fails I would still retain all my data? I also understand that one drive is for parity information but not really understanding how one drive can protect the information on the three other drives. What if the parity drive fails?

As mdgm explains, xraid-2 distributes the parity blocks. Though even if it did not, the parity blocks can be recomputed from the data blocks, as long as the data blocks are intact. Distributing parity blocks just evens out the reads and writes across the drives (which helps performance, and evens drive wear).

More details if you want them: The 4-drive raid array is organized as horizontal stripes, with each stripe containing one parity block and three data blocks

block 1, block 2, block 3, parity
block 5, block 6, parity, block 4
block 9, parity, block 7, block 8
parity, block 10, block 11, block 12

The way the parity works is that

block 1 XOR block 2 XOR block 3 XOR parity = 0

XOR is an "exclusive or" operation, but you can envision it as a strange form of addition.

block 1 + block 2 + block 3 + parity = 0

When a disk fails (say disk 2), the NAS can compute the missing block by solving the equation above.
block 2 = 0 - block1 - block3 - parity

With XOR, this turns out to simplify to
block 2 = block1 XOR block3 XOR parity

The way this is set up, no matter which disk fails, the disk is recovered by XORing the other three.

With RAID-6 (dual redundancy) the math is more complicated, and amounts to solving 2 simultaneous equations. Each stripe has a second "parity" block sometimes called Q, which is computed using from the data blocks using a different equation. With two drive failures, you end up with two equations with two unknowns - which the NAS has to solve to recover the disks.

Thank you for the clarification. I get it now. Complicated, but I get the general idea of how the RAID works.

I now have the Ultra 4 Plus loaded with four 2TB drives. One question. I loaded all the drives, connected the NAS to network and power, turned it on and opened RAIDar (which I had previously installed when setting up the Ultra 2 Plus). One other note is that two of the four drives were from my Ultra 2 Plus and still have their data intact. I assumed that the process of loading all the drives in the Ultra 4 Plus would give me an option of wiping the drives for maximum expansion capacity as StephenB had mentioned in the previous post. Anyway, when I opened RAIDar the Ultra 4 Plus was discovered and all four drives were recognized. The Ultra 4 Plus immediately started re-striping the drives and sent me this e mail notification "Volume expansion or migration started. Do not interrupt the system during this time. When finished, email notification will be sent to the alert contact list". The Home page of Frontview indicates "Volume C: Online, X-RAID2, 3 disks, 71% of 1841 GB used". Frontview never gave me an option otherwise and I was afraid to open the setup wizard for fear that it would interrupt this restriping process.

Is the restriping process erasing the data on the hard drives from the Ultra 2 Plus or is it expanding the volume to include the two new hard drives and keeping the data intact? I would like to ensure maximum expansion capacity as StephenB had mentioned and wanted to make sure what is happening now will allow for that or if I will need to actually do a factory default and wipe after this initial restriping process is completed. Bummer if that is the case because obviously you all know how long this takes. Also, the NAS drive still shows up in the Finder on my mac and shows all the shares I previously had setup on the Ultra 2 Plus. Is this normal?

Thanks again, you guys are fantastic with your responses. I hope this post is helpful to others who are also upgrading.

Steve 46 wrote:
or is it expanding the volume to include the two new hard drives and keeping the data intact?

It's doing this. It's detected that you've migrated the disks and is keeping data intact.

Steve 46 wrote:
Frontview never gave me an option otherwise and I was afraid to open the setup wizard for fear that it would interrupt this restriping process.

Interrupting the process would be to e.g. power off the NAS. Opening Frontview would not interrupt this process.

Steve 46 wrote:

I would like to ensure maximum expansion capacity as StephenB had mentioned and wanted to make sure what is happening now will allow for that or if I will need to actually do a factory default and wipe after this initial restriping process is completed. Bummer if that is the case because obviously you all know how long this takes. Also, the NAS drive still shows up in the Finder on my mac and shows all the shares I previously had setup on the Ultra 2 Plus. Is this normal?

Yes it's normal. You can migrate disks as shown here: http://www.readynas.com/kb/faq/boot/how_do_i_migrate_disks_over_from_an_existing_readynas_to_another

However if you have your data backed up and want to start open from a clean state, there is no need to wait for the current syncing to finish. Open RAIDar now, click setup and go to System > Update > Factory Default, select to perform the factory default and follow the prompts. The NAS will restart and give you a 10 minute window in which you can choose the RAID mode via RAIDar (need to click Setup) and after that will wipe the disks and setup the RAID array.

One more thing. What version of RAIDiator is on the ReadyNAS?

RAIDiator 4.3.0

That's the RAIDar version. I was asking about RAIDiator (the firmware on the NAS itself). Firmware version would show ok home page of Frontview

Firmware version is 4.2.20

The Ultra 4 completed the factory default and RAID setup and I've created my shares, users, and groups. Only one odd thing. I created a Gryphon, Media, and Office share but when I connect to the NAS I also see a share created for Steve_C (that is my user name) even though there is no Steve_C share in the share listing in Frontview. Thoughts? Otherwise the upgrade went well.