Filesystem root and data partition on laptop

Message

KejPi · Post by **KejPi** » Mon May 30, 2011 2:31 pm

Hello All,

In past on my desktop computer I used to used reiserfs as a filesystem for / (many small files, including also portage) and xfs as filesystem for data (mixture of small files like mail and big files like movies or music).

Now I have got a new laptop that I am going to install and at the moment I am not sure what would be the best filesystem to use. I have trying to find some clear advise on internet but it is more and more fuzzy for me. At the moment am am more or less decided to use ext4 ad data partition but I am not sure about / partition as it might have significant impact on system performance. Is ext4 also a good choice for that? Basically - root partition will contain everything except /boot and /home. In past I had a bed experience with ext3 and portage tree as it had a very low performance and very big disc occupation. I have some doubt if ext4 will be better.

What would you recommend?

Thanks!

Post by **NeddySeagoon** » Mon May 30, 2011 6:14 pm

KejPi,

extX filesystems are all the same for disk use. The block size on the partition is either 1k, which is good for lots of small files, 2k or 4k.
The value selected automatically is normally 4k, as partitions tend to be big today.

You can do your own tuning at filesystem create time. Rieserfs scores over extX as it does "tail packing" which reduces the wasted space in the last block of every file. Speed wise there is little to choose between them.

I use a lot more partitions than you are suggesting, so I can have portage on a non journelled small blocked extX filesystem.
I also use lvm2, so if I get the partition sizes wrong, it doesn't matter.

KejPi · Post by **KejPi** » Tue May 31, 2011 9:44 pm

Thanks for your answer. You have convinced me to use ext4 also for /. By the way, I have just found out that may hdd has 4k sectors, so for that reason it would be better to use ext4 with 4k blocks and aligned partitions, right?

Post by **NeddySeagoon** » Tue May 31, 2011 10:03 pm

KejPi,

Proper partition alignment for drives with 4k physical sectors is important regardless of the filesystem.

When partitions are misaligned, the drive has to perform read/modify/writes to fix it. On a rotating drive, on one pass of the data under the head, the drive can read the sector. If you are lucky, before the data comes under the head again, the misaligned data can be merged, then the data can be written to the disk. There is anecdotal evidence that this slows drive accesses by about a factor of 30x.

Its a similar process for SSDs but now you have to wait for erase cycles or the block can be remapped.

Either way, it all happens at a lower level than the filesystem.