Rebuild fails to complete

This case is mostly about maintenance, when 220 Black Armor fails to complete resync

I have a Seagate black armor 220 which keeps trying to repair a volume after a had drive failed as part of RAID1. I replaced the disk, added the member drive ran the S.M.A.R.T checks on the drives and started to recover … it gets to around 80% and the restarts. There are no error messages and this has been looping for about a week now…

Any ideas as to why it wont complete the recovery process and rebuild the raid volume? or how I can trouble shoot it?

This one is easy. The NAS is still readable, so the troubleshooting consists of five steps,

  1. Back up data from NAS to some other location.
  2. Destroy RAID1 in NAS.
  3. Replace disk which is still not replaced.
  4. Reconfigure RAID1 and wait for resync.
  5. Restore from backup.

The problem most likely is that the second (non-replaced) disk has developed a problem; SMART test can sometimes miss a bad sector, or the interpretation of SMART data either by the customer or by the NAS firmware is excessively tolerant. The inability to complete the rebuild is more significant observation than a SMART test result.

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Prior Planning Prevents Poor Performance

People seem overly concerned about how to do the recovery should their NAS go down. These two cases (first, second) concern Thecus NASes.

If I create RAID 1 and the N3200Pro hw fails beyond repair (for whatever reason), can I take out one of the HDDs out and read the files on it in a Linux or Windows PC? I am only interested in reading the data once at that stage, rebuilding the RAID is a non-issue …

and

Assuming that I have a Thecus N2310. Assuming that I have a disk that *was* part of a RAID1 but the other disk is missing. What steps do I need to do with the disk and the N2310 to rebuild the RAID array and get the data off please?

I was describing this at some length in another post, but just for a short repeat, if you are worried about recovering data should the NAS dies, why not have a backup for it? The data may get damaged for reasons other than a total and utter NAS hardware failure. Lightning strike, software issue, or a number of other reasons will damage both sides of the RAID1 at the same time. RAID does not replace a backup.

Prevention is good

Every now and then, people plan and go to great lengths figuring how to do data recovery before the actual data loss occurs.

What type of file system does the ix2 use with hard drives? For safety, I’d like to know how to recover data from the drives if the ix2 fails. I do not like the idea of relying on some hidden proprietary format that requires the ix2 to be able to retrieve my data in case of failure.

Anyone know how to read the disk formatted by the ix2 from a PC running any operating system?

There is no hidden proprietary format actually. Lenovo/Iomega uses run-of-the-mill Linux software and filesystems. However, the great confusion ensues little further in the discussion, mixing up filesystems with RAIDs, RAIDs with backup, single-disk RAID1 with a single partition, you name it.

Well, let’s spell it out

  1. Any NAS would use this-or-that form of RAID.
    1. Even if you have a single disk in a multi-bay NAS, it will have a single-disk RAID, most likely RAID1, to avoid changing data format if you add a second drive.
    2. Furthermore, if you have a single-bay NAS, it is still likely to have a single-disk RAID, to achieve compatibility across the entire model lineup (and specifically the ability to move the drive to the multi-bay model).
  2. Most modern NASes use one of the standard Linux filesystems, XFS, EXT3, EXT4, or BTRFS.
  3. If there is no damage to the data on disks, or the damage is minor, and assuming skilled operator, a properly configured Linux PC will read the data if all disks are connected at the same time.

But, the most important question here is: if one plans for data recovery before the actual loss, why do not have a backup instead of recovery?

 

SHR on two identical disks

The set of questions from here, while SHR-specific, applies to NETGEARs X-RAID as well.

I have a DS213j set up as Synology Hybrid RAID (SHR) with 2 2TB disks. What happens if the DS213j fails? Are the disks just mirrors so that I can connect either to a PC and see it as an external drive and recover the data? If not would it be better to change to RAID 1? What are the advantages of SHR over RAID 1?

SHR means Synology Hybrid RAID. The advantage of SHR is that SHR can better utilize capacity of mixed size disks, and SHR supports some weird disk upgrades which are normally done by deleting and rebuilding the traditional array.

However, if we are talking two identical disks and no plans to upgrade, SHR is in effect the same as RAID1, so there is really no choosing one or the other.

Iomega StorCenter ix2-200 device fails when powered

This is about an Iomega/Lenovo device, Iomega StorCenter ix2-200

When I power on the ix2 the ‘!’ light blinks red. I can’t connect to it…, under ‘dashboard’ everything seems as usual except the pie chart showing space usage is not there. … when I click on Users or Shared Storage it says Disks Not Ready. The selected function is not available due to the state of the disks.

… what to do from here?

Although it is not specified anywhere in the post, further discussion suggests there are two disks in the NAS. Another crucial bit of information missing is the RAID level. There are three possibilities with two disks:

  • RAID1, when two disks are identical;
  • JBOD, when the data is first stored on one disk, then once the first disk fills up, the second one is used;
  • RAID0, when the data is interleaved between two disks.

Red exclamation sign on a StorCenter indicates either a non-recoverable disk failure, or some kind of severe logical failure.

First thing to try, as rightly suggested in follow-ups to the original post, is to try booting with just one disk. This works if the array is RAID1. Two tests must be done because even with RAID1, there is an even chance of leaving the bad disk in.

If the array is RAID0 or JBOD, and the drive ha indeed failed, the drive must be repaired first. If there is no mechanical problem, but rather some logical issue, we can help you with RAID0, but not with a JBOD.

 

Know your RAID level

One ReadyNAS owner seems to be confused about what RAID level is (and was) used on its ReadyNAS Duo (full story).

I have a readyNas Duo with 2x 1Tb disks in raid. … I had to reset the NAS, unfortunally i holded the reset button to long so the disks are wiped clean….

After the reset i upgraded to the latest firmware and let the disk sync.

… is my data lost, or are there way’s to recover the data?

i tried to recover my data with [RecoverMyFiles] …without success…I checked only one disk since i wanted to have the other one as an backup to be examined by a company … [and they] … think my disks were not in mirror but in striping mode…I can’t check this ofcorse but i never saw more totall space then the size of one disk.

This looks real bad. There are two things we know for sure:

  1. this is ReadyNAS Duo, and
  2. there are two physical drives.

and that’s all. There are four conflicting bits in the above quote relevant to the RAID level.

  1. [did] let the disk sync suggests RAID1. RAID0 does not need any kind of sync.
  2. wanted to have the other one as an backup indicates owner’s belief that the array is RAID1
  3. company … thinks … striping mode, that’s pretty straightforward.
  4. never saw more totall space than the size of one disk, which again points to RAID1.

Problem is, it is fairly easy to recover data either from a RAID0 or from a RAID1. Home NAS Recovery, as one obvious example, can work either way, and does not even need to know the RAID level beforehand. However, if the initial array was RAID0, and then after a reset the NAS switched to RAID1 mode and copied contents of the one disk to the other disk, there is nothing left to recover.

 

ReadyNAS RAID Levels

ReadyNAS comes in a wide variety of RAID levels, none of them seemingly matching the standard. There are (in different ReadyNAS devices)

  • Flex-RAID
  • X-RAID
  • X-RAID2

Flex-RAID is the most simple of them all. It is a stand-in for manual configuration. Once you choose Flex-RAID, the system asks you to choose between any of the standard RAID levels, and if you go for multiple arrays, then how many disks are allocated to each of the arrays.

X-RAID and X-RAID2 both hide RAID settings from user. Both will automatically expand array if more disks are added, or if enough disks are replaced with larger ones and the array can be expanded maintaining redundancy. Internally,

  1. on one disk, it is just a simple partition,
  2. as the second disk is added, that simple partition is converted to a RAID1,
  3. at the addition of the third disk,  RAID1 is converted to a RAID5,
  4. as more disks are added, RAID5 is reshaped to accommodate additional disks.

The exact difference between X-RAID and X-RAID2 is sort of moot. For all intents and purposes, once the RAID crashed, they are the same.

Home NAS Recovery works with any of these configurations except

  1. where disks of different sizes are involved
  2. where multiple RAIDs are involved; Home NAS Recovery requires RAIDs fed to it one by one. If you have multiple RAIDs and you do not remember which disks form which RAID, your case is likely to end up in a data recovery lab anyway.