Holy Slow Drobo Batman!

[OmegaRed1723]

I recently reached the storage capacity of my 4-bay Drobo loaded with four 1TB disks and have started the process of adding larger drives to the array. What a time consuming process! After inserting the first new 2TB drive, the Drobo Dashboard software estimated 51 hours to redistribute the data. After over 24 hours of rebuilding, the software still estimates 27 hours until completion. If this trend continues the redistribution process will take over 60 hours to complete.

To add insult to injury, this will create zero additional usable space; all the extra capacity is saved for expansion which requires another larger drive to be added. Assuming the second redistribution takes as long as the current one is, I'm looking at 5 days of rebuilding time for a relatively small amount of data (2.4TB).

The Drobo is the first RAID-type array I have used, so I don't have much to go off, but doesn't that rebuild time seem inordinately long? Does anyone have experience redistributing data on another RAID5 device? How long did it take? I understand that Drobo uses a proprietary technology that isn't actually RAID5, but it's in the same ballpark.

 

[MacForScience]

I recently reached the storage capacity of my 4-bay Drobo loaded with four 1TB disks and have started the process of adding larger drives to the array. What a time consuming process! After inserting the first new 2TB drive, the Drobo Dashboard software estimated 51 hours to redistribute the data. After over 24 hours of rebuilding, the software still estimates 27 hours until completion. If this trend continues the redistribution process will take over 60 hours to complete.

To add insult to injury, this will create zero additional usable space; all the extra capacity is saved for expansion which requires another larger drive to be added. Assuming the second redistribution takes as long as the current one is, I'm looking at 5 days of rebuilding time for a relatively small amount of data (2.4TB).

The Drobo is the first RAID-type array I have used, so I don't have much to go off, but doesn't that rebuild time seem inordinately long? Does anyone have experience redistributing data on another RAID5 device? How long did it take? I understand that Drobo uses a proprietary technology that isn't actually RAID5, but it's in the same ballpark.

2.4TB re-distributed is not a quick process imagine dividing data up into pieces then copying it to other drives, removing old copies making duplicates etc. DROBO isn't really a standard raid with its variable hard-drive size capability so the process of re-distributing is more complex because you cannot distribute the data in any form of an even manner.

Cheers

 

[Gav2k]

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Your second drive won't take as long don't worry.

 

[OmegaRed1723]

Thanks for the input. My main concern is running these drives for 24/7 while redistributing the data increases the possibility of one of the other drives failing, resulting in a catastrophic loss of data. It's "only" media that can be replaced, but the time involved with that would be enormous. I suppose the next step is to add a second Drobo for redundancy. One of these days...

 

[darknite38]

After inserting the first new 2TB drive, the Drobo Dashboard software estimated 51 hours to redistribute the data. After over 24 hours of rebuilding, the software still estimates 27 hours until completion. If this trend continues the redistribution process will take over 60 hours to complete.

24 hours of rebuilding with 27 hours left equals 51 hours total? Not 60 =D

 

[OmegaRed1723]

24 hours of rebuilding with 27 hours left equals 51 hours total? Not 60 =D

My statement was if the trend continued -- meaning if the estimated time remaining kept rising when it should have been decreasing -- it would have taken 60 hours instead of the initial 24 it estimated. In the end, it took approximately 54 hours to redistribute the data across the new disk. I just popped in the second new drive, and already it's telling me 42 hours until completion. Something tells me that this is way slower than it should be, but the end result will give me a decent amount of headroom before I have to add another drive.