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

If you do a 'df -h' you will see that there are a couple extra partitions.

df -h
Filesystem                Size      Used Available Use% Mounted on
rootfs                    9.7M      7.4M      1.7M  81% /
/dev/root                 9.7M      7.4M      1.7M  81% /
/dev/sda2               915.9G    915.8G    158.5M 100% /mnt/HD_a2
/dev/sdb2               915.9G    915.9G     42.3M 100% /mnt/HD_b2
/dev/sda4               486.2M     23.7M    462.5M   5% /mnt/HD_a4
/dev/sdb4               486.2M     16.0k    486.2M   0% /mnt/HD_b4

It dowsen't tell where DNS is keeping extra 30GB. Rest of partitions take about 1GB total.

fordem wrote:

Try looking at the partition structure - you'll find that the DNS-323 had several partitions on each disk, in addition to the one that is used to store the data.  One is used as a swap partition, and another is used for 'housekeeping' chores.

Can I acces to those partitions, or browse them at least?

Last edited by wujo11 (2010-09-30 16:05:05)

Another couple of things you should be aware of.  First off what is a TB to the OS might not be a TB to your drive manufacture.  The manufactures have a tendency to call 1000 GB a TB (they did the same for 1000 MB when they crossed over to 1 GB).  When of course the number should be 1024.  They have been doing since hard drives went over 1 GB (well when they went over 1000 MB )  This depends on the manufacture though.

The other thing to know is that the there is always overhead to a file system, so just formatting the drive is going to consume some of that space.

Personally I think one of the best places to see the disk space usage is just look at the status page on the DNS-323 web admin page.  My 1TB drive shows a has a capacity of 983454 MB.  1TB should be 1024 * 1024 MB or 1048576 MB (By OS method of calculating) for a true TB.  Looks like more then 6 Gig is lost to formatting, until you take a trip to the disk spec sheet.  In their words "Guaranteed Sectors      1,953,525,168".  The sector they are talking about is 512 bytes.  So that gives 1000204886016 bytes.  Notice the nice round 1000?  So this will show up as 1000 GB, but it isn't really 1TB, which would be 1024GB. 

With fdisk -lu I see:
Disk /dev/sdb: 1000.2 GB, 1000204886016 bytes
255 heads, 63 sectors/track, 121601 cylinders, total 1953525168 sectors
Units = sectors of 1 * 512 = 512 bytes

   Device Boot      Start         End      Blocks  Id System
/dev/sdb1              63     1060289      530113+ 82 Linux swap
/dev/sdb2         2088450  1953520064   975715807+ 83 Linux
/dev/sdb4         1060290     2088449      514080  83 Linux

What's odd about the number?  Starting with the full drive space in bytes not just one partition (first line) of fdisk output:

1000204886016 / 2^30 = 931.51 GB

This is exactly what the manufacturer of my drive guaranteed (1,953,525,168 * 512 = 1000204886016).
And you say 931.51 GB isn't a 1TB?  You are right, it is 1 trillion "human" bytes (10^12), not 2^40, but that is what manufactures are calling a 1 TB drive.  And that is the point.  You can expect about 930 GB on a 1 TB drive.  The computer talks in powers of 2, and the drive manufactures are talking in powers of 10 these days.

The exact size that your manufacturer might call a 1 TB drive might not be the same as mine.  Because of the way they manufacture drives, and because of possible bad sectors, so almost none of the drives from different manufactures are going to have the exact same amount of bytes.  They are just guaranteeing that you will have 10^12 or more bytes (well at least mine is "Seagate", yours might state something a bit different).


BTW (1TB should be 1024 * 1024 MB or 1048576 MB) = 1099511627776 bytes (a base 2 -> 1 TB).

Last edited by chriso (2010-10-01 01:15:16)

Oh sorry, I thought you were talking about my post.