Drobo

Will partition alignment improve performance?

Can partition alignment help performance on a DroboElite? Is it even possible?

In the past, when I would create partitions on a RAID volume, I would create partition where the starting offset was a multiple of the stripe unit size of the array. More recently, I simply use a 2K sectors (1MB) offset. But, in those RAID arrays, I knew the array’s stripe unit size and it never changed during the life of the array. If the misalignment resulted in data being written

The offset used when the Drobo Dashboard created my 2TB NTFS partition is 32KB. But, I don’t know if it matters with the Drobo’s “BeyondRAID”. Since I can’t control the RAID stripe unit size and the fact that it could change on-the-fly if I change the physical drive configuration, using a multiple of the stripe unit size seems to be a waste. But, could a 1MB offset work regardless of drive configuration (number and size of each drive in the 8 bays)?

I’m currently getting pretty reasonable performance in mb/sec and IOPS especially considering the cost and sharing bandwidth with the single NIC. But, if I can eek out a little more, why not do it?

Partition alignment if for OSes that have direct access to the drive’s geometry. This is not the case for Drobo, as it presents a virtual geometry to the system.

Long story short, alignment from the OS/host side does not matter when using Drobo.

You should verify, however, that the Drobo’s firmware supports 4K sector drives when the disk pack is set up, which it does in the current firmwares that I know of.

Thank you. Upon initial power up (3 weeks ago), I had installed 5 2TB Hitachi drives (I haven’t checked 4K spec on those drives). After that first power-up, the firmware and the dashboard got updated to the latest. After that, the first volume was created, partitioned, and formatted. In this sequence, do you think it’s likely that the drive pack was “set up” with 4K support? Can Drobo support tell positively by diagnostic data?

Best regards,

I don’t know if a firmware update can actually re-align the data on the disk pack or not. My gut feeling is that it wouldn’t, but Drobo has all sorts of black magic I still don’t understand.

DRI can probably tell you whether the disk pack was set up properly aligned or not from the logs though.

That’s an interesting question and sparked my interest & curiosity to find out the technical correctness. By making a few assumptions such as u r using NTFS and most likely U have Windows Server or Win7 as the guestg OS, and also very likely the host is on VMware (Correct?), then the next quetion is which version? The partition alignment was no longer needed after the release of ESX 4/vSphere but we have never tested or even tried to run the famous partition util from Quxxx/VizionXXXX to v-Optimze the DroboPro or Elite. Worth setting up in a test lab when I have time. :slight_smile: