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

When you delete a file you're not actually touching the 16gb data at all, you're just removing the inodes that point to the blocks where the data resides on the disk. IIRC, files with 12 or less blocks of data will be accessed the fastest, then you start moving in to indirect blocks (inode poiting to a block of pointers which point to data blocks), and then double & triple indirect blocks. I can't remember what happens to the indirect blocks when you remove a file - I would have thought that removing the primary inode would be sufficient but maybe I am wrong and this is why it's taking so long.

If you wanted to speed things up when using large files, increasing the block size used on the file system would probably help as it would reduce the number of indirect blocks used. However, I believe this would have to be done when you format the disk (i.e: you'd need a reformat!).

Yes, 4kb is max (although 8kb for alpha I think). Re: formatting on the dns-323 - I'm not sure if it's safe or not to be honest, most of the web based functions are all binary so you can't really see what they're doing. Specifically I haven't looked to see how the dns-323 checks if the filesystem is "ok", I would've though that formatting /dev/md0 should be fine in terms of the dns-323 still recognizing the mirror (if that's what you're using) but I wouldn't guarantee it. Reformatting is also a bit of a drastic step without investigating first.

How are you deleting the file? Via samba? ftp? telnet? It could be a problem with samba etc... I'll create a 16gb file on my dns-323 now and delete it via telnet to see how long it takes...

I can delete with this problem over samba and after login by telnet. The problem is with working my devices with samba connection.
I am using dremboxes as recorders. I have tried to use nfs, but it is useless in dns323. I can record only as no_root_squash , else the data files are created in 0 lenght . All files are created with root owning and I am not able to delete it during data editing on pc in windows (samba).
Next is not existing free dns client for windows except buggy (very buggy ) unix tools for win. It makes me using only samba.

Firstly I would try to run e2fsck on the disks, secondly chechk which process is actually choking the computer.

If you have Seagate disks in your enclosure do not forget to remove the compatibility jumper that they ship with. See my next post.

Maybe Samba is running out of memory when you make concurrent requests? I have seen strange issues when opening some folders- there would be a massive amount of network activity and the computer appears to be frozen for 30 seconds... I am on a Gigabit network- would you see a lot of network activity between the workstation and the dlink box when deleting the files?

I have checked the the network activity during deleteing two files , each 8G length. It is small. Smaller than 0.1% of my bandwidth.

Maybe your ext2 is badly fragmented. I had once 89% fragmented ext3 and it was very slow plus has eaten all RAM for caching. And unlikely NTFS/FAT it does not get fixed by moving the files in and out. You have to reformat.
Fragmentation report can be obtained from e2fsck

You really want to break your issue down to basic elements and address each one separately to find out what is the problem:
1. Hard disk compatibility issue
2. Hardware fault
3. Disk fragmentation
4. Network communication problems
5. DNS-323 configuration issue

skydreamer wrote:

Maybe your ext2 is badly fragmented. I had once 89% fragmented ext3 and it was very slow plus has eaten all RAM for caching. And unlikely NTFS/FAT it does not get fixed by moving the files in and out. You have to reformat.
Fragmentation report can be obtained from e2fsck

You really want to break your issue down to basic elements and address each one separately to find out what is the problem:
1. Hard disk compatibility issue
2. Hardware fault
3. Disk fragmentation
4. Network communication problems
5. DNS-323 configuration issue

I can't speak for efs(n) file systems, but fragmentation has very little impact on the deletion of large files on NTFS/FAT file systems - large numbers of files is of course different.

With NTFS/FAT essentially what happens is the directory entry pointing to the first block is deleted and the blocks are marked as available in the allocation table, I would assume the process is not significantly different with linux file systems.

e2fsck -n /dev/sda2
e2fsck 1.32 (09-Nov-2002)
/dev/sda2 was not cleanly unmounted, check forced.
Pass 1: Checking inodes, blocks, and sizes
Pass 2: Checking directory structure
Pass 3: Checking directory connectivity
Pass 4: Checking reference counts
Pass 5: Checking group summary information
Free blocks count wrong (51034071, counted=49474309).
Fix? no
Free inodes count wrong (60927926, counted=60927865).
Fix? no
/dev/sda2: ********** WARNING: Filesystem still has errors **********


I have no idea what should do with it. If I have to fix, why the ext2 is using if it is not stable ?

I have noticed this with deleting large files in Windows Explorer as well for years

it is not a new thing (atleast to me) to have wait while deleting large files before you can navigate to a different directory

Tom0000 wrote:

The no_root_squash makes a problem for me, because each file created this way over nfs has root privillages and no way to delete anything over samba connection. Do you have any any idea for this problem fix ?

I don't have a PS3, but can't you tell the PS3 to use a different user/uid and group/gid over NFS?

Tom0000 wrote:

Have you tried use nfs for your dreambox ?
I have found 1 problem. 
If I am using no_root_squash in export , the dreambox is working fine. If I will use any other option the dreambox will write correct only eit file and all ts files will have 0 length.
The no_root_squash makes a problem for me, because each file created this way over nfs has root privillages and no way to delete anything over samba connection. Do you have any any idea for this problem fix ?

I found nfs very slow especially when used with or from dreambox. The transfer rates I was getting were in the range of 500kB/s.
Samba is a much better option, with speeds 2,500 kB/s when launched from Dreambox and dlink is mounted there as cifs. It is even faster through a third PC having dlink and dreambox shares mounted there. The speed was 3,500 kB/s but it left out most files as it tripped over the international characters-  Dreambox assigns funny names to the films from Taquilla, Premiere or TPS.

Maybe you can try to run top when deleting the files to see what is the biggest drag on the d-link's CPU.