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Hannah Vernon's questions

Martin Hope
Hannah Vernon
Asked: 2016-05-18 12:10:22 +0800 CST
  • 5

If disks have 512-byte physical sectors, and you have 10 disks using RAID 50 with a 1MB stripe-size how does that work at the disk level?

Correct me if I'm wrong, but conceptually, there would be 2 spans each consisting of a RAID-5 array of 5 disks, one mirrored to the other. Therefore, a "stripe" would consist of 4x256KB chunks of data, plus a single 256KB of parity data per stripes? or does a "stripe" include the parity?

What if you consider a 12-disk RAID 10 array? There would be 6 mirrored pairs of disks, with striping over those mirrors. So, for a 1MB stripe size, the stripe would be divided by 6, for 174,762.666 bytes per-disk, which works out to 341.333 physical sectors per stripe. Is that really 342 physical sectors per stripe?

For those who wonder why I'm asking; I am attempting to determine the most efficient number of disks relative to the type of RAID, with the best stripe size.

Also, I have seen https://en.wikipedia.org/wiki/Nested_RAID_levels prior to asking this question. In fact, I've done a ton of work looking for low-level design details on a vast multitude of SCSI / SAS / RAID / SAN vendor sites, and have not seen anything that talks about the actual on-disk format of stripes. Stripes are only talked about at a highly conceptual level, which is fine, but doesn't really answer the question.

raid
Martin Hope
Hannah Vernon
Asked: 2015-06-13 08:21:37 +0800 CST
  • 4

I am attempting to determine the "hardware" version of numerous VMWare VMs. I don't have access to the vSphere console.

The VMWare Tools Service is installed, and C:\Program Files\VMWare\VMWare Tools\vmtoolsd.exe --cmd "info-get" looks promising, however I cannot find any details about what key name to specify.

Is there some other method such as looking at VMWare device driver versions or perhaps a wmic query?

vmware-esxi
Martin Hope
Hannah Vernon
Asked: 2015-03-20 13:23:47 +0800 CST
  • 0

I have a Windows Server 2012 VM that has only been assigned a single core; I'd like to know if the HAL for the machine is multi-core capable before requesting more cores be added to the VM.

Is there some WMIC command, regedit value, or some other indicator?

I know in previous versions of Windows, I could tell by looking at the "oroginal file name" property for %SystemRoot%\System32\hal.dll -> Windows Server 2012 only shows "hal.dll".

I've looked through the MACHINE registry hive, but can't find anything close to meaningful. I've also Googled "site:microsoft.com windows server hal multiprocessor", but none of the results are helpful.

windows-server-2012
Martin Hope
Hannah Vernon
Asked: 2012-09-05 05:45:38 +0800 CST
  • 4

We have a Dell EqualLogic PS6510 RAID Array. I have full access to the web-based "PS Group Manager" app, as well as the "SAN Headquarters" app. I have hunted high and low, and searched Google for the answer, but I cannot for the life of me determine the stripe size of the RAID-50 array we have configured.

Does anyone with experience on an EqualLogic PS6510 know how to find the stripe size?

Additional Info:

Page 19 of http://i.dell.com/sites/doccontent/business/solutions/engineering-docs/en/Documents/dvs-enterprise-reference-arch-citrix-blades-shared.pdf talks about the default stripe size being 64K.

raid