Dead Drive Pegasus2 R4

  • Last Post 06 July 2021
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Chris Conroy posted this 01 July 2021

One drive is showing a major problem in the Promise Utility.

In the past, if I've been able to mount the drive I've had success repairing it. Is this possible? I don't see a way to do this with the Promise Utility.

It's RAID0, so I assume if I can't repair the drive that I can add a new drive and restore from a backup?



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R P posted this 01 July 2021

Hi Chris,

It's hard to say anything specific from such a general problem description, but...

Is that drive is offline, then the RAID0 is offline and won't be mountable.

If you have critical files you might force it online and hope it stays online long enough to copy off the important files.

But generally what you say here is correct.

It's RAID0, so I assume if I can't repair the drive that I can add a new drive and restore from a backup?

Note, if these are the original drives that shipped with the Pegasus, there is a possibility that other drives might fail. Years ago a datacenter published a drive FAILURE study involving at a huge number of drives. The most interesting result to me was that when one drive failed, there was usually another drive ready to fail. And I've actually seen this happen.

So it might be an idea to consider buying new and larger drives and using RAID5 instead of RAID0.

Chris Conroy posted this 01 July 2021

RP- thanks so much for your help.


I've replaced the drive and I'm restoring from a backup. I will look into replacing the drives.



Chris Conroy posted this 02 July 2021

One more question - I've looked at the compatability document (Pegasus2_Compatibility+List+v2.10-20160311.pdf) and some of the drives listed are quite old. There are more recent drives by the manufacturer. Are those okay to use?


For example, Seagate T3000DM001 is listed, but difficult to find. ST3000DM007 is available and easier to find. Is that an acceptable drive for the Pegasus2 R4?



R P posted this 06 July 2021

Hi Chris,

The ST3000DM007 looks to be a later model of the ST3000DM001, so it should be a good replacement.

Here are some general rules...

1. Essentially any spinning drive can be used as a spinning drive replacement but it's best to replace with a drive with similar characteristics. A later drive of the same drive family is usually the best choice if available.

2. It is not suggested to replace a 7200 rpm drive with a 5400 rpm drive. This will result in a performance hit and possibly cause faster wear.

3. It is not recommende to use shingled drives (SMR) in a RAID. Some new drives are shingled but not labeled as such.

4. Larger drives can be used, and the older the drive the more likely it is that this will be necessary. I had to replace some 750GB Segates with 1TB and later 2TB drives as 750GB drives are no longer available. Of course only 750GB of the new drives will be used.


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