Hello,
I noticed something unusual today.
If I "du" a small file (couple of bytes) in CentOS 5, it tells me the file is using 8kb, while I was expecting 4kb which is the block size I'm using.
I tried this on several CentOS 5 machines, both x86_64 and i386:
$ echo test >test.txt $ ls -l test.txt -rw-rw-r-- 1 filbranden filbranden 5 Mar 11 17:24 test.txt $ du -h test.txt 8.0K test.txt
If I do the same on a CentOS 4 machine:
$ echo test >test.txt $ ls -l test.txt -rw-rw-r-- 1 filbranden filbranden 5 Mar 11 17:25 test.txt $ du -h test.txt 4.0K test.txt
On all machines I tested, both CentOS 4 and CentOS 5:
# tune2fs -l /dev/xxxxx ... Block size: 4096 Fragment size: 4096
I could not find any differences that would explain the behaviour. Have you seen this before? Can you reproduce it on your systems? Do you know how to get the CentOS 4 behaviour?
More on the point: I'm migrating some data from CentOS 4 to CentOS 5, it's around 70GB of millions of small files. I would like it to still take 70GB, not 140GB. For now, I'm working around this issue by using "-T small" to mke2fs, I'm not sure if it's going to have the effect I want, and I'm not sure about any other impact (performance?) it might have on my filesystem.
Thanks, Filipe