Recovery is possible but it depends on what caused the corruption. If the file is just truncated, getting some partial result out is not too hard; just run gunzip < SMS.tar.gz > SMS.tar.partial which will give some output despite the error at the end. If the compressed file has large missing blocks, it’s basically hopeless … Read more
Add an HTTP Header Manager to the Thread Group in your Test Plan. Add the name-value pair: Name: Accept-Encoding Value: gzip,deflate,sdch This will ensure that all JMeter requests use HTTP compression. To verify: Add this Listener to the Thread Group: View the Results Tree Run your test plan View the Sampler result tab for one … Read more
If you’re still looking for a more detailed overview, I’ve written up a description of the gzip deflate process, along with source code, at: http://www.infinitepartitions.com/art001.html
It is apparently due to a misunderstanding resulting from the choice of the name “Deflate”. The http standard clearly states that “deflate” really means the zlib format: The “zlib” format defined in RFC 1950 [31] in combination with the “deflate” compression mechanism described in RFC 1951 [29]. However early Microsoft servers would incorrectly deliver raw … Read more
Use strace. First, you need to detect PID of nginx process: # ps ax | grep nginx 25043 ? Ss 0:00 nginx: master process /usr/sbin/nginx -c /etc/nginx/nginx.conf 25044 ? S 0:02 nginx: worker process Ok, so 25044 is the worker process. Now, we trace it: # strace -p 25044 2>&1 | grep gz open(“/var/www/css/ymax.css.gz”, O_RDONLY|O_NONBLOCK) … Read more
This works for any file size: zcat archive.tar.gz | wc -c For files smaller than 4Gb you could also use the -l option with gzip: $ gzip -l compressed.tar.gz compressed uncompressed ratio uncompressed_name 132 10240 99.1% compressed.tar
zcat(1) can be supplied by either compress(1) or by gzip(1). On your system, it appears to be compress(1) — it is looking for a file with a .Z extension. Switch to gzip -cd in place of zcat and your command should work fine: gzip -cd CONN.20111109.0057.gz | head Explanation -c –stdout –to-stdout Write output on … Read more
To decompress a gzip format file with zlib, call inflateInit2 with the windowBits parameter as 16+MAX_WBITS, like this: inflateInit2(&stream, 16+MAX_WBITS); If you don’t do this, zlib will complain about a bad stream format. By default, zlib creates streams with a zlib header, and on inflate does not recognise the different gzip header unless you tell … Read more
What about just getting a listing of the tarball and throw away the output, rather than decompressing the file? tar -tzf my_tar.tar.gz >/dev/null Edited as per comment. Thanks zrajm! Edit as per comment. Thanks Frozen Flame! This test in no way implies integrity of the data. Because it was designed as a tape archival utility … Read more
You can also use the tar flag “–use-compress-program=” to tell tar what compression program to use. For example use: tar -c –use-compress-program=pigz -f tar.file dir_to_zip