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Jared
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Dell PERC S100 RAID Specs

Mon Feb 29, 2016 4:08 pm

I'm helping a guy remotely to recover a RAID 5 from a Dell Server using a PERC S100 controller (found model in metadata). Unfortunately it looks like someone initialized the drives and overwrote the partition tables. Anyone know what the default stripe size is on this controller? The manual appears that it's a left sync parity rotation, but no mention of stripe sizes.

Normally I'd just figure it out, but it's taking long because I have to scan each time due to the lost partitions.

jol
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Dell PERC S100 RAID Specs

Mon Feb 29, 2016 7:12 pm

Jared wrote:Source of the post but no mention of stripe sizes

Code: Select all

6.3.5 Stripe Size
Stripe size cannot be specified by user at create VD time. The stripe size is automatically set by the SW
RAID based on the total capacity and number of disks assigned to the virtual disk RAID levels.

https://www.dell.com/downloads/global/p ... _Paper.pdf

the same is here

Code: Select all

Stripe size        Stripe size is determined by a PERC S100 adapter/PERC
                  S300 adapter algorithm. Stripe size cannot be configured by
                  the user.

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Jared
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Dell PERC S100 RAID Specs

Mon Feb 29, 2016 9:39 pm

Yes, I did come across that in my research. But, still never mentions any actual stripe "sizes", just the fact that the user can't configure it. I've already ruled out the possibility of it being smaller than 64K, but not sure if it might be bigger than that yet.

jol
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Dell PERC S100 RAID Specs

Tue Mar 01, 2016 11:39 am

since the stripe size depends on total capacity and number of disks assigned, if the controller (PERC S100) is still working (and/or you have access to it), I would rather take the same no. of drives + same capacity, and build the RAID again, than trying to figure it out, and wasting long hours of scanning each configuration.
if it's not working or don't have access to it, maybe buying one is still worth it (didn't checked the price) ?!

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Jared
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Dell PERC S100 RAID Specs

Tue Mar 01, 2016 5:23 pm

Like I said, I'm helping someone remotely so not a case where I'm going to invest in buying a crappy old RAID controller or one where I have access to it. Would have been really easy too, if I just had a partition table to work with.

jol
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Dell PERC S100 RAID Specs

Wed Mar 02, 2016 12:09 am

Jared wrote:Source of the post Like I said, I'm helping someone remotely

right, my bad, didn't noticed

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Jared
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Dell PERC S100 RAID Specs

Wed Mar 02, 2016 7:45 pm

Finally beat this RAID. Right A-Sync parity rotation and 64Kb block size was the magic trick. Absolute last configuration I was going to try was the correct one. Doh! :roll:

Moving on to an EMC RAID for tomorrow now. :o

jol
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Dell PERC S100 RAID Specs

Wed Mar 02, 2016 8:35 pm

Jared wrote:Source of the post Right A-Sync parity rotation and 64Kb block size was the magic trick

since it has been made automatically depending on the size & no. of drives (as stated in the manual) would you mind telling us those details (if someone may come across the same situation) ?

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Jared
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Dell PERC S100 RAID Specs

Thu Mar 03, 2016 7:44 am

It was three 500GB drives in RAID 5. My guess is that the controller just always uses 64KB block size and that "automatic" business is just a lot of bunk, but I don't have a way to test it.

jol
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Dell PERC S100 RAID Specs

Thu Mar 03, 2016 2:21 pm

Jared wrote:Source of the post It was three 500GB drives in RAID 5.

thanks
Jared wrote:Source of the post My guess is that the controller just always uses 64KB block size and that "automatic" business is just a lot of bunk

probably

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