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July 26th, 2017 04:00
Strip Element Size - Stripe Size - Raid10 - Perc h730p - change Strip Element Size without destroying data
Hello,
Our configuration:
R730xd with Perc H730P (2GB)
2 SAS Drive 15K 300GB as Raid 1 (Host OS RHEL 7)
20 SAS Drives 15K 600GB as Raid 10 (VMs Microsoft W2K8R2 W2012R2 - NO database servers - Exchange is hosted on a different server)
As a research facility we have a broad spectrum of files and file sizes that are generated.
File sizes generated vary between office files (e.g. small Word files, large PowerPoint files), large research files (bigger than 1MB in size) and lot of small research files (smaller than 50KB).
The "Stripe (Element) Size" I did choose for the initial RAID10-Virtual Disk setup was 128K (a mistake?).
As I would like to check/compare the write/read performance with a different "Strip Element Size"/Stripe Size (e.g. 64K, 32K), I would like to ask the following question:
- according to user "pcmeiners" in a posting (from 2005) (en.community.dell.com/.../17394995) he is describing a step by step instruction to change the "Strip Element Size"/Stripe Size without destroying the data on the VD.
- in another posting from "pcmeiners" (en.community.dell.com/.../19509110) he was writing,that he was able to manage/change the Stripe Element Size "...on raid 1 and raid 10 for tweaking the stripe size for databases many times in the past, without destroying data, with no issues...".
Question:
Is this manual/workaround still valid/working for the current Dell server models (R730xd with Perc h730p which is based on the LSI3108)?
It would be very helpful changing the "Strip Element Size" without setting up everything again (would be very! time consuming).
Thanks for your help
rukl
DELL-Josh Cr
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July 26th, 2017 10:00
Hi,
Stripe size does not seem to be an editable field when you do a reconfigure. So I don’t see a way to do it without data loss.
DELL-Josh Cr
Community Manager
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July 26th, 2017 11:00
You could try it, if it doesn’t work you are going to need to reload anyway. It shouldn't work because the data amount on each stripe is going to be different. Most likely it will corrupt all of the data.
rukl
3 Posts
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July 26th, 2017 11:00
Yes, I know that the field is not editable, but as I wrote, "pcmeiners" provided a way to change the stripe size:
Unfortunately a bracket was added to the links I provided; here are the correct links:
en.community.dell.com/.../17394995
en.community.dell.com/.../19509110
In the first link he is providing a step by step instruction, mentioning to delete the VD but NOT!!! to initialize the VD (please see yourself)...
I would like/need to know if this procedure would also work with the current Dell servers R730xd and LSI-based Dell controllers like the Perc h730p?
Thanks
rukl
pcmeiners
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August 1st, 2017 10:00
A couple nights ago I was thinking about the last time I change the stripe size. It was just before Sandy, which killed my server due to the salt water. I did change the stripe on a raid 10 in the machine, as it was the only array I had in the machine, and the last time I benchmarked an array. At this point I have no idea if the procedure still works with the newer controllers, basically it is retagging with a twist....curious if it still works.
rukl
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August 3rd, 2017 00:00
Hello pcmeiners,
I did NOT succeed in changing the Strip Element Size to 64KB without loosing access to the data on VD1 with RAID10 (I did follow the instruction step by step WITHOUT initializing the "new" VD).
As the host OS (placed on VD0 with RAID1) was unaffected (I did not change the Strip Element Size here), Data on VD1 (RAID10) were not accessible anymore.
Therefor all VMs were gone. All VMs were backed up, so I could recreate/restore everything (with the new Strip Element Size of 64KB :-) on VD1
I do not know, if the same would have happend with Windows as Host OS, nor can I say if the special configuration (we are using two identical servers - configuration see below - which provide HA and FT for the VMs on the RAID10-VD1; software System "Everrun Enterprise" is based on RHEL) was "responsible" for not recognizing the "new" VD1 anymore.
Anyway: Performance on VMs with the new Strip Element Size is recognizable better.
Many thanks for your help (also from your private messages), even if the instruction did not work in this case.
Best
rukl
Our configuration:
R730xd with Perc H730P (2GB)
VD0 - 2 SAS Drive 15K 300GB as Raid 1 (Host OS: RHEL - CentOS7)
VD1 - 20 SAS Drives 15K 600GB as Raid 10 (VMs Microsoft W2K8R2 W2012R2 - NO database servers - Exchange is hosted on a different server)
Host OS - Everrun Enterprise - based on RHEL - CentOS 7
pcmeiners
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August 3rd, 2017 09:00
So with the newer Percs the stripe size change does not work. The OS involved would have no affect on this, as the raid configuration does not involve any operating system.