I'm testing casync to sync VM images, for now I'm using random binary data to test it, I have seen that when I change just 2 bytes on the binary file casync requires 55% chunks from remote server and only uses 45% seed data.
on webserver:
100MB.bin file created using dd from /dev/urandom
pwd
/root/test
ls -lah 100MB.bin
-rw-r--r--. 1 root root 100M May 31 21:10 100MB.bin
Zero bytes written as sparse files: 0B
Bytes cloned through reflinks: 0B
Chunk requests fulfilled from local store: 0 (0%)
Bytes used from local store: 0B (0%)
Chunk requests fulfilled from local seed: 0 (0%)
Bytes used from local seed: 0B (0%)
Chunk requests fulfilled from remote store: 7539 (100%)
Bytes used from remote store: 472.0M (100%)
Time spent seeding: 1ms (0%)
Total extract time: 19min 14.649s
I go to the server and open the binary file, change 2 random bytes and save.
Zero bytes written as sparse files: 0B
Bytes cloned through reflinks: 0B
Chunk requests fulfilled from local store: 0 (0%)
Bytes used from local store: 0B (0%)
Chunk requests fulfilled from local seed: 3384 (44%)
Bytes used from local seed: 213.2M (45%)
Chunk requests fulfilled from remote store: 4155 (55%)
Bytes used from remote store: 258.7M (54%)
Time spent seeding: 29.660s (4%)
Total extract time: 11min 29.752s
Any idea why it takes so many chunks for a small change?
Hi,
I'm testing casync to sync VM images, for now I'm using random binary data to test it, I have seen that when I change just 2 bytes on the binary file casync requires 55% chunks from remote server and only uses 45% seed data.
on webserver: 100MB.bin file created using dd from /dev/urandom
pwd
/root/test
ls -lah 100MB.bin
-rw-r--r--. 1 root root 100M May 31 21:10 100MB.bin
casync -v make 100MB.bin.caidx .
ls
100MB.bin 100MB.bin.caidx default.castr
mkdir -p /var/www/html/casync/
cp 100MB.bin.caidx /var/www/html/casync/
/bin/cp -rp default.castr /var/www/html/casync/
I now go to the client and download the file
On client:
casync -v extract http://remoteserver/casync/100MB.bin.caidx
Zero bytes written as sparse files: 0B Bytes cloned through reflinks: 0B Chunk requests fulfilled from local store: 0 (0%) Bytes used from local store: 0B (0%) Chunk requests fulfilled from local seed: 0 (0%) Bytes used from local seed: 0B (0%) Chunk requests fulfilled from remote store: 7539 (100%) Bytes used from remote store: 472.0M (100%) Time spent seeding: 1ms (0%) Total extract time: 19min 14.649s
I go to the server and open the binary file, change 2 random bytes and save.
hexedit 100MB.bin
casync -v make 100MB.bin.caidx .
cp -frp default.castr /var/www/html/casync/
/bin/cp -rp default.castr /var/www/html/casync/
On the client:
casync -v extract http://remoteserver/casync/100MB.bin.caidx --seed=/root/test
Zero bytes written as sparse files: 0B Bytes cloned through reflinks: 0B Chunk requests fulfilled from local store: 0 (0%) Bytes used from local store: 0B (0%) Chunk requests fulfilled from local seed: 3384 (44%) Bytes used from local seed: 213.2M (45%) Chunk requests fulfilled from remote store: 4155 (55%) Bytes used from remote store: 258.7M (54%) Time spent seeding: 29.660s (4%) Total extract time: 11min 29.752s
Any idea why it takes so many chunks for a small change?
Thanks,