No Volumes No Shares - Superblock Issue?

[fvdw]

any news?

[NigelBrownless]

Any News?

Current Update. We have completed a scan of 10480 MB, and still going.
It has found something at Block 4097, 7001, 7041 & 8193.

[fvdw]

So it scanned 7 GB in 3 days. Thats about 260kB per second.
Why is it so slow :scratch. To scan 500GB with this speed wil take 210 days. I did the test on an nas with an armda 370 cpu which is faster then the kirkwood on your device. That did 10 MB in oa few seinds.vI will do a speed check on a kirkwood device to see if your speed is normal.
To speed up the scan we could use larger blocks. But I will need to adapt the script to scan larger blocks and need to see what happens if there are multiple XFSB strings inside and that it does not store big blocks as the standalone kernel runs from ram and it has only limited storage space (about 500MB)

[fvdw]

My 5big2 with same cpu as 2big2 scanned 100 MB in 45 seconds using block size of 1 MB, then it would take 62 hours to scan 512 GB. So why you nas is so slow might indicate a disk problem. Anyhow I tried bigger blocksize but that doesn't increase speed, seems the grep command inside the script to find the XFSB string takes time and max out the cpu.
Need to see if there is another way.
Attached an updated scan script. In this one you can set block size and start block. Could be handy to scan parts of the array
arguments to be given: device blocksize blocks-to-scan start-block
example

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scanmd2.sh /dev/md4 1 512000 1

will scan with blocks of 1 M it scans 512000 blocks starting with block 1

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scanmd2.sh /dev/md4 1 512000 512001

will scan with blocks of 1 M it scans 512000 blocks starting with block 512001

You could also try to scan /dev/sda2 or /dev/sdb2 instead of md4 to see if that improves speed.
Also remember that the files stored by the standalone kernel will be gone when you teboot as they are stored in ram. So copy them before reboot.

You can abort the script by pressing ctrl-c

[fvdw]

I have written a C program that can scan faster, on my 5big2 it scanned 1GB in 4 minutes, so that would mean 500GB in in 200 minutes or 3 hours and 20 minutes
It will give different out it will mention the byte where a XFSB string was found.
It stores that output also in a file with name output.txt.
The program will ask you to give the number of 1 M blocks to scan.
To see what is actually present we will need to use dd command to read at that spot
For example this is output on my 5big2 , I specified to scan 500 blocks
(it gives several hits as it is a firmware partition)

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root@fvdwsl-5big2:/share/1000/effe2 # ./scanmd3 /dev/sda2
Read 1 M blocks to read: 500
to=524288000
k=3 XFSB string found at byte 8015156
k=3 XFSB string found at byte 9198000
k=3 XFSB string found at byte 137408352
k=3 XFSB string found at byte 292986208
k=3 XFSB string found at byte 292986672
k=3 XFSB string found at byte 323011052
k=3 XFSB string found at byte 332398932
k=3 XFSB string found at byte 415689360
k=3 XFSB string found at byte 416681944
k=3 XFSB string found at byte 416825824
k=3 XFSB string found at byte 418618720
k=3 XFSB string found at byte 420017644
k=3 XFSB string found at byte 425601788
k=3 XFSB string found at byte 425705524
k=3 XFSB string found at byte 429227108
k=3 XFSB string found at byte 430524112
k=3 XFSB string found at byte 436056044
k=3 XFSB string found at byte 439067956
root@fvdwsl-5big2:/share/1000/effe2 #

To check the locations found with an XFSB string we will need commands like this to put the content in a file.

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dd if=/dev/sda2 bs=1 skip=439067956 count=512 of=check439067956.img

The files we can open with a hex editor to see if it is a superblock or not and what is its content

[NigelBrownless]

OK. So I'm going to abort the current Scan (Currently at 11170 MB), and then save the IMG Files it has created so far. I will then upload them.

I'll then do a reboot of the NAS and then try to run the new C Scanner.

[NigelBrownless]

Attached are the 4 instances that the Script version of the Scan found in a single RAR file.

I also attached the one found in Block 1, in case it's useful.

[NigelBrownless]

So using the new C Version of the Scan, I ran it on the SDA2 disk for 500 blocks.

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./scanmd3 /dev/sda2
Read 1 M blocks to read: 500
to=524288000

It reported the following...

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k=3 XFSB string found at byte 0

And took about 1min 54 Seconds to complete. So looks like my timings are similar to you?

I will kick it off with 500000 blocks, and let you know when it is done.

[fvdw]

super7001 and super7041 are no superblocks
super4097 and super8193 contains a string XFSB followed by a linefeed. I also so that in super1.img
So not sure if it is a superblock we will need to copy some bytes around that later although I would not expect a superblock so close at the start of the file system.
Interesting is that they are at the beginning of a 4096 byte block just like super1.
But lets see if the C scanner brings up more candidates

[fvdw]

And took about 1min 54 Seconds to complete. So looks like my timings are similar to you?

I will kick it off with 500000 blocks, and let you know when it is done.

yes that looks similar to my trail