Does anyone know if 4k sectors will be handled better by the kernel in Centos6?
I'd like to copy backups to a 750Gb laptop type drive for offsite storage
but
the best write speed I can get is about 8MB/sec even with dd to the raw disk
which shouldn't have an issue with partition alignment.
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Les Mikesell
lesmikesell at gmail.com
On 02/06/11 1:14 PM, Les Mikesell wrote:> Does anyone know if 4k sectors will be handled better by the kernel in Centos6? > I'd like to copy backups to a 750Gb laptop type drive for offsite storage but > the best write speed I can get is about 8MB/sec even with dd to the raw disk > which shouldn't have an issue with partition alignment.what are you using on dd as the blocksize (bs=) ? should be a fairly large multiple of 4K, like 1048576 (eg, 1MB writes). I get 50-80MB/sec writes to a laptop drive hooked up to my windows desktop when I'm cloning said laptop drives. if you're only seeing 8MB, something is very wrong.
> the best write speed I can get is about 8MB/secA while back I researched 4k sector drives since most new drives have them now. There is a problem with speed if you get the partition wrong. The answer seems to be to creating a partition with 1 meg of unpartitioned space preceding the first partition. This causes sector 2048 to be the first sector of the partition, and avoids the problem. Newer versions of gparted do this for you automatically when you use it to create a partition.