On 1/27/14, 1:16 AM, Masato Minda wrote: > Dear Ext4 Developer; > > I've copied the files from VxFS to EXT4, I saw the message “Directory > index full!”. I've checked the search engine and found these mails. > > http://www.spinics.net/lists/linux-ext4/msg25058.html > http://www.spinics.net/lists/linux-ext4/msg25069.html > > Our Ext4's block size was 1024. I've changed the block size from 1024 to > 4096. Our problem was solved. But I have question. > > How many files to create in one directory in 4096 block size? > I think that it is about 3 million files with perfect hashing. > > 16*(4096-16)/8*(4096-8)/8*3/4= 3M > > Is this correct? It will depend on the length of the filenames. But by my calculations, for average 28-char filenames, it's closer to 30 million. There are (4096-32)/8 indices per block, or 508. There are 2 levels, so 508*508=258064 leaf blocks. The length of each record for 28 char names would be 32 bytes. So you can fit 4096/32 = 128 entries per leaf block. 258064 leaf blocks * 128 entries/bock is 33,032,192 entries. I recently made a spreadsheet to calculate this. I'm not sure if I am doing google docs sharing and protection correctly, but this might work: https://docs.google.com/spreadsheet/ccc?key=0AtdHTZsZ8XoYdE1IUXlDb1RXQkdPM3F4YWpfNGhMbFE&usp=sharing#gid=0 -Eric > Thanks in advance. > > -- > Masato minmin Minda <minmin@xxxxxxxxxx> > Japan Registry Services Co., Ltd. (JPRS) > > -- > 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 > -- 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
