DSM-G600, DNS-3xx and NSA-220 Hack Forum

SUMMARY: how do I align existing JBOD partitions to 4k sectors with all the data intact on EARS-type hard drives?


LONG STORY:  I guess I made a mistake of buying & not reading.

I bought two Western Digital Green Caviars which are so called "Advanced" Format Drives -
On the surface  WD20EARS (2TB, 64MB cache) provides good performance for the money ....

Since this was to be upgrade - I had to borrow second DNS-323 from a friend - and I left them over the weekend to copy all the data
from the second NAS (2x 1TB) to the new disks.

After it was done I happily installed fun_plug..... only after a few days I noticed that performance degraded significantly: read rates used to be 14MB now they are 7-8MB/s

Only than I have started to read up on the forum )-:


The bottom line questions is
Q: is there any way to resize partitions in JBOD formated hard drives to achieve 4K sector alignment ?


I have started (default firmware formating) with the following partition table:

Disk /dev/sdc: 2000 GB, 2000396321280 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907024065 sectors
Units = sectors of 1 * 512 = 512 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1              63     1060289      530113   82  Linux swap
/dev/sdc4         1060290     2088449      506047   83  Linux
/dev/sdc2         2088450  3907024064  1952459775   83  Linux


I decided to connect my HDDs one by one to my Linux machine and use gparted to resize the partition and in the process align them properly. The process was safe and partially successful.

I managed to get to this point:
Disk /dev/sdc: 2000 GB, 2000396321280 bytes
255 heads, 63 sectors/track, 243201 cylinders, total 3907024065 sectors
Units = sectors of 1 * 512 = 512 bytes

   Device Boot      Start         End      Blocks   Id  System
/dev/sdc1            2048     1060863      538146   82  Linux swap
Warning: Partition 1 does not end on cylinder boundary.                   
/dev/sdc4         1060864     2084863      506047   83  Linux
Warning: Partition 4 does not end on cylinder boundary.                   
/dev/sdc2         2088450  3907024064  1952459775   83  Linux


I think that SWAP and ROOT are now properly aligned, but gparted refuses to recognize JBOD partition (/dev/sdc2)

Does anybody have any suggestions how to resize JBOD partition without damaging it?


(btw: do I need to worry about Warning: Partition 1 does not end on cylinder boundary ?)

Last edited by andrez (2010-11-21 23:16:55)