Looks like no one’s replied in a while. To start the conversation again, simply ask a new question.

Promise Pegasus r6 Physical Disk is marked as DEAD due to forced offline state

I had this on two of my drives around 24 hours of first unboxing - so far I am fidning it hard (and slow) to get a satisfactory answer from Promise as to what caused this other than the suggestion from support that "the controller forces a going to be defective drive offline to prevent any further issues".


I am trying to work out whether to return the system and invest in something else, because after this failure I googled around and found quite a comments from people having problems with Pegasus RAIDs and many, like me, being unimpressed with their support.


There are of course two side to every argument so I am really just trying to see if others have had this problem, if so, what they did about it? I am still waiting for a response from support, having sent them the relevant system reports, to see if I lost any data. I do have backups but I want to be able to trust the system.


All thoughts and experiences gratefully recieved!

Posted on Mar 23, 2014 4:31 PM

Reply
10 replies

Mar 23, 2014 5:30 PM in response to Tim Ashley

Your top-notch Promise enclosure does not want to build RAIDs out of drives that it sees as marginal.


That is excellent.


It is taking good care for you. Better to have it be more discriminating at the outset than to build a marginal RAID and have it fall apart in heavy use.


--------


That they are not able to communicate this to you is tragic. Send the lot of them back for Re-Training.


.

Mar 23, 2014 5:40 PM in response to Grant Bennet-Alder

I wish it were that simple! The unit is delivered preconfigured as RAID 5. After several hours for the initial 'synchronisation' process, I copied about 2tb of data to the logical drive, and, that having gone well overnight, I dragged another 1tb of files and folders onto the drive. It was within a split second of doing this that the drive alarm buzzer went off and two of the physical drive lights went red and the unit stopped functioning.


I was able, failing to get a swift answer from Promise, to google a solution that allowed me to use the terminal to force both drives back online, since which time they have been working fine BUT I can't tell if any data was lost and I can't get any more comprehensive answers out of support... Though they have told me that I shouldn't have put the drives back online from the terminal.

Mar 23, 2014 5:49 PM in response to Tim Ashley

When you own a High-Availability RAID system, you need to be prepared to remove drives that it says cannot cut it in a RAID, and use a Spare instead. You do need spare drives on hand.


The marginal drive may be fine for less-strenuous purposes, where re-tries are better tolerated.


You can add a "seen as failing" drive back into a RAID ONCE. If it EVER misbehaves again, it need to be gone from the RAID.

Mar 23, 2014 6:25 PM in response to Tim Ashley

No offense intended, but do you really need RAID at all?


It can be a lot more expensive because you have to be merciless with any drive that "acts up". And you usually need at least one spare drive just sitting around.


Many users find scrupulous backups are just as likely to give good results without the extra expense.


--------


If you want to start a flame war, just post "Reliability of RAID 5 ?" as a Topic. There are some really strong opinions out there.

Mar 23, 2014 6:44 PM in response to Tim Ashley

Oh. The other problem with RAID, especially RAID 5, is that it is not inherently faster.


RAID is faster when you can overlap seeks from multiple drives on the second and subsequent large chunk of data from the SAME file PROVIDED no Reads or Writes to other files intervene.


So you really need a Source RAID and a separate Destination RAID, and you should be looking at Striped, not RAID 5 (which computes checksums coming and going). Striped is "unstable" in that a drive failure takes out ALL the data on both drives.

Mar 23, 2014 6:52 PM in response to Grant Bennet-Alder

Ok, so if you wanted really fast access to a 4tb Lightroom library, and you wanted it to be as 'safe' as possible but not splash out on SSDs, what would you use? Something that's understandable to someone who is fundamentally a photographer who wants to leverage the speed of his new Mac Pro, but isn't an IT specialist.


Really appreciate this BTW!

Mar 24, 2014 6:25 AM in response to Grant Bennet-Alder

Thank you Grant.


I am going to return the Pegasus - I finally heard back from their support that one of the drives needs replacing and for my money, a company that ships a product with a drive that lasts 24 hours and then fails without leaving any indication as to what if any data was lost, which provides very poor documentation (none in the box other than a quickstart guide) and IMHO also poor support, does not merit any confidence!


I am going to re-group and reconsider, and try to find a more relia ble and far less time wasting solution than what (broken) Promise can offer!

Promise Pegasus r6 Physical Disk is marked as DEAD due to forced offline state

Welcome to Apple Support Community
A forum where Apple customers help each other with their products. Get started with your Apple ID.