Data recovery and disk repair questions and discussions related to old-fashioned SATA, SAS, SCSI, IDE, MFM hard drives - any type of storage device that has moving parts
February 6th, 2018, 17:44
I an working on a RAID 6 from a Dell with a PERC controller, but am having difficulty rebuilding the array. I like working in R-Studio due to the visibility of the RAID layout with a RAID 6. However this one is XFS so need UFS. What are UFS equivalents to
- Rotating N Data Continuous
- Rotating N Data Restart
February 6th, 2018, 19:10
I think that can be done by just using Left Sync/Async and then adding a value to the "Rotation Shift Value" box equal to the number of data blocks before the P and Q. So if it's an 8 drive array you'd add a 6 there to shift it to start on the right side after the data.
At least that's what I think it is... Haven't had to do much RAID 6 work in UFS either.
Did you give R-Explorer (the updated version of UFS) a try? It might just read out the metadata automatically.
February 6th, 2018, 20:12
Thanks I will do some testing.
February 8th, 2018, 8:46
For Dells Perc controllers, R-explorer unable catch config automatically.
Regarding equivalency between UFS and R-studio for Raid6 particular cases (left-symmetric = standart)
One way to make similar construction is to set shift by 1 in UFS, how explained above, or other (easier as for me) just put 1st drive to the end.
In UFS raid6 default rotation goes like that 1 2 3 4 P(XOR) P(Reed-Solomon) ....
In R-studio raid6 default rotation is P(Reed-Solomon) 1 2 3 4 P(XOR) ....
February 8th, 2018, 11:49
Great information. I wish UFS would have a GUI of the layouts, it would make it a lot easier. I also need to invest in R-Explorer.
February 8th, 2018, 13:17
What I would probably do in such a case is to identify a region that has a lot of jpg images all together. Build the RAID every which way in R-Studio and just scan that small region each time and analyze the results. Once you're consistently getting pictures that open and are larger than stripe size multiplied by the number of drives, you know you've got the right configuration. Then it's just a matter of replicating it in UFS/R-Explorer. At least that way you won't have to do the trial and error of the stripe size and drive order in UFS. You'll just have to figure out how the other details translate over.
February 8th, 2018, 13:58
Yes I have been doing exactly that. This RAID has had a rebuild..... you know how that goes......
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