Re: [Ext2-devel] [RFC 0/13] extents and 48bit ext3
Jeff Garzik <[email protected]>
| Newsgroups | gmane.linux.file-systems,gmane.comp.file-systems.ext2.devel,gmane.linux.kernel |
|---|---|
| Message-ID | <[email protected]> |
Theodore Tso wrote: > Inodes per group and inode blocks per group are maintained > across an online resize. So there is no difference in inodes per > group for a filesystem created at size S1 and resized to size S2 > (using either an on-line or off-line resize), and a filesystem which > is created to be size S2. Here are real numbers, which illustrate how the above two statements contradict, and how the second statement is false: blkdev A, formatted with a 50MB filesystem block size 4096 block count 12800 (size S1) inodes per group 12800 blkdev A, formatted to full capacity (~350GB) block size 4096 block count 95472256 (size S2) inodes per group 32768 Case 1: online resize from 50MB to 350GB Result: inodes per group == 12800 (it remains the same) Case 2: mke2fs blkdev A, with no block-count restrictions Result: inodes per group == 32768 Thus, each inode group holds fewer inodes per group in case #1 than #2. Thus, case #2 has greater inode density than case #1. Overall, a) mke2fs chooses optimal values based on creation-time block count b) online resize does not change these values thus the values are no longer optimal. And in this case, they are never -more- optimal, and potentially -less- optimal. Jeff - To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html