I have a 2TB Samsung EVO SSD that I just installed to replace on older, smaller, model. This is a shared resource for several OS installations. I have 4 partitions on the drive as not all of the partitions are used for every OS that shares the resource. I did a bonnie++ test and performance on this drive is about half of what I expect it to be.
The output of fsidk -l is,
$ sudo fdisk -l /dev/sdb Disk /dev/sdb: 2000.4 GB, 2000398934016 bytes, 3907029168 sectors Units = sectors of 1 * 512 = 512 bytes Sector size (logical/physical): 512 bytes / 512 bytes I/O size (minimum/optimal): 512 bytes / 512 bytes Disk label type: dos Disk identifier: 0x01033206 Device Boot Start End Blocks Id System /dev/sdb1 * 4096 511991549 255993727 7 HPFS/NTFS/exFAT /dev/sdb2 511995904 716795903 102400000 83 Linux /dev/sdb3 716800000 1740799999 512000000 83 Linux /dev/sdb4 1740804096 3907029167 1083112536 83 Linux
I believe that this is an alignment issue but I am having trouble determining the proper start and end sectors.
Even though the physical sector size is listed as 512, I believe that it is actually 4096 under the hood. This means that the partition should start on a sector boundary that is a multiple of 4096. The first partition (sorry it's ntfs in this case) starts at sector 4096 (2MB), so that looks correct, but I'm not sure where it should end. According to the printout above, this partition covers 255993727 blocks. This value divided by 4096 is 62,498.4685059, which is not a whole number so it seems as if the end sector is not optimal.
The partition needs to be ~250GB. I have no idea how to calculate where the end sector should be. I used GParted to create the partition and you can only specify a partition size in MB. You can align to MiB, cylinders, or none, but I don't know the correct option there either. I could use fdisk to make the partition if that makes more sense.
If the first partition is not optimally aligned, the others probably are not as well. Can I fix this by just resizing partition sdb1 to end at a different sector? If so, how many MB should the partition size be?
I think if I can answer that I can figure out the rest. Please let me know if I need to post additional information.