2012/9/4 Theodore Ts'o <tytso@xxxxxxx>: > On Tue, Sep 04, 2012 at 09:59:55AM +0800, Yongqiang Yang wrote: >> Hi Kevin, >> >> Ted has sent out the patches on online resizing for meta_bg and >> 64bits, so you can have a try again. It seems that the bug in >> e2fsprogs has been fixed. > > Make sure you use the latest version of the kernel patches that I just > sent out. There quite a number of bugs in the Yongqiang's original > patch set which I tripped over while I was testing 64-bit resize --- > and please note that there are definitely still rough edges > (especially for in cases where the file system was created < 16TB, but > with the 64-bit feature and resize_inode features enabled). There may > also be bugs for the straightforward case of resizing very large file > systems. > > So while I very much appreciate users giving the code a try and > sending us feedback, please do think twice before using this code on > file systems with data that hasn't been backed up recently. (Of > course, being good System Administrators you are all keeping --- and > verifying --- regular backups, right? :-) > > Regards, > > - Ted I had done some simple and quick test. The following is the result. Kernel: 3.4.7 + 5 patches e2fsprogs: 1.42.5 + 2 patches The format command I used is: mke2fs -t ext4 -m0 -b 4096 -F -O 64bit,meta_bg,^resize_inode /dev/md0 nnnn Case 1: Simplly resize 1st step: resize from 14T to 18T => ok 2nd step: resize from 18T to 20T => ok (calculate_minimum_resize_size issue gone) 3rd step: resize from 20T to 21T => ok Case 2: case 1 + file read-write (just like Anssi did) 1st step: resize from 14T to 20T (5368709120 blocks) => ok 2nd step: resize from 20T to 5368709170 blocks => same kernel bug_on Case 3: case 2 + Yongqiang's 2 patches 1st step: resize from 14T to 20T (5368709120 blocks) => ok 2nd step: resize from 20T to 5368709170 blocks => ok Basically I think the resize funtionality should be ok. However I also observe some performance drop. That is, the time needed for mke2fs, mount and e2fsck are longer than before. Here is some detailed data: For 12TB with 64bit,meta_bg,^resize_inode mke2fs: 54.699s mount: 12.108s e2fsck: 1m52.027s For 12TB without 64bit,meta_bg,^resize_inode mke2fs: 39.763s mount: 0.897s e2fsck: 1m17.554s For 20TB with 64bit,meta_bg,^resize_inode mke2fs: 1m25.090s mount: 19.992s e2fsck: 2m55.048s For 20TB without 64bit,meta_bg,^resize_inode mke2fs: 1m3.660s mount: 1.458s e2fsck: 1m56.055s Yongqiang had told me previously that it may be caused by using meta_bg. I am still wondering is there anything we can do to improve the peroformance? Thanks a lot. Regards, Kevin Liao -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
