I have an Ubuntu 10.04.1 LTS linux server which is experiencing some weird issues... I just tried to download a 440 MB
tgz archive over HTTP using wget, and when expanding it with
tar -xzf filename.tgz I received:
gzip: stdin: invalid compressed data--crc error
Finding this odd I renamed the file
filename-bad.tgz and downloaded it again. I received the same error on the second download... The site listed an md5 checksum for the file so I checksummed both the two download attempts to see if maybe this file was just corrupt...
The two files had different checksums!
So I downloaded this file to my local workstation and ran
md5sum on it there. This time, the MD5 checksum was correct, and the file extracted properly. So I copied the file from my workstation to the server and ran
md5sum on that copy. It was a new md5sum, different from the correct md5sum and different from the two other attempts!
Here is the detail of the server:
- Intel(R) Core(TM) i5 CPU (Dual Core)
- 8GB RAM
- Software RAID5 array using linux md devices and 3 1TB SATA drives
- 2 ethernet cards, connected to two different networks in our office (the wired and the wireless network)
I suspected maybe the RAID array was degraded/malfunctioning, so I ran
mdadm --detail and it reported the state was
clean and all drives were in
active sync. To further test, I copied a 1GB file from an SD card to the RAID array, and the md5sum of that file verified.
What could be going on?
EDIT: Output of
cmp -l as requested:
324268145 115 105 324268657 274 264 324269297 332 322 324270577 345 344 324270833 155 154
EDIT2: I just realized one of the copies I have actually does have the correct MD5 checksum, so I copied the file from my local machine two more times and both times the checksum was correct! So a few more tests are in order here...
EDIT3: I am now unable to reproduce this issue. Which sounds like bad RAM to me. Will run memtest tonight, any other ideas welcomed!
EDIT4: Ok. Now this is weird. The issue is 100% reproducible when copying the file to specific VMWare virtual machine is running on the server. If I copy the file to that virtual machine, sometimes if I immediately copy the file to the host, the problem is reproducible.
scp also sometimes says this when copying to the virtual machine:
Received disconnect from 10.1.0.73: 2: Packet corrupt
These all seem to me to be clues of bad RAM. Does everyone concur? Any other possible explanations?
EDIT5: Solved. Gee, what on earth could have been causing this problem? I just don't understand.... :-)
(I did test the RAM on this system right after I bought it, which was two-three months ago... oh well. Looks like it's time to call Dell...)