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Forum Discussion
Non-optimal partition alignment
I have a non-Netgear SAS expansion chassis connected to my RD5200 running OS6, so I have to manually create volumes via SSH. When I do that, I am careful to create an OS and swap partition exactly as the GUI does, in addition to the main one. I know they won't be used now, but they could if the drives are swapped to the main chassis or exported/imported to another NAS.
Anyway, when I do create these, parted warns me that the resulting partitions are not aligned for optimal performance. Fdisk and gdisk refuse to even create that alignment. Is this affecting the speed of ReadyNAS devices? I have verified that the partitioing I am specifying is identical to what the GUI will create (with OS 6.9.5) on the same drive by letting it actually do so with the drive mounted internally in a standard NAS.
If it matters, I have thus far only done this with 512N sector drives.
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Sandshark wrote:Anyway, when I do create these, parted warns me that the resulting partitions are not aligned for optimal performance. Fdisk and gdisk refuse to even create that alignment. Is this affecting the speed of ReadyNAS devices?
My RN526 disks are partitioned this way:
Device Start End Sectors Size Type /dev/sda1 64 8388671 8388608 4G Linux RAID /dev/sda2 8388672 9437247 1048576 512M Linux RAID /dev/sda3 9437248 11721041071 11711603824 5.5T Linux RAID /dev/sda4 11721041072 19532873679 7811832608 3.7T Linux RAID
Note the data volume was vertically expanded (which is why /dev/sda4 exists). All of these start on 4K boundaries.
I believe parted (and gdisk) presume the optimal alignment is to start all partitions on 1 MiB boundarys (2048 sectors) - and the ReadyNAS isn't doing that. But I don't think there is any performance degradation in the NAS setup. As best I can tell, the motivation for the 1 MiB value is only to be conservative over the long term. AFAICT, 4K alignment is enough to give optimal performance with current disks.
Yep, that's the way they normally are, and the observations I made still apply. Parted complains they are non-optimal and fdisk and gdisk refuse to do it. But Parted will let you do it and just complain when done in a single commend or make you confirm if done one at a time.
I read much of what you said in other forums, that fdisk and gdisk are going with a conservative "one size fits all" approach. But was wondering if anyone from Netgear would comment on specifics for the NAS and if there is an impact for larger drives without 512N sectoring. If not now, in the future.
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