Ramesh wrote: > Hi Eric, > > Thanks for your prompt and informative reply. > >>>> do you mean sector size of the block device, or block size of >>>> the fileystem? > For our device sector size is 4906 bytes. But the maximum allowed > data chunk to read/write is 512( a.k.a Block size), restricted by > specification. > > By referring the wiki pages of EXT3 > (http://en.wikipedia.org/wiki/Ext3), I saw the below table. > > Block size Max file size Max filesystem size > 1 KiB 16 GiB <2 TiB > 2 KiB 256 GiB <4 TiB > 4 KiB 2 TiB <8 TiB > 8 KiB[limits 1] 2 TiB <16 TiB Above, block size means the filesystem block size. For ext3, all 32 bits should be safe on recent kernels and userspace, so I think the max filesystem sizes listed above are too small by half. IOW, 4k filesystem blocks -> 16T max filesystem size. > And by taking the values with the table, then for 512 bytes block > size, Max file system supported is 1 TB only. Please correct me, if I > assumed wrongly. you cannot have a 512 byte block size in ext3, 1k is the minimum. >>>> I guess it doesn't matter much either way, 2^32*512 is 2T. > > In that 32 bit, it using the MSB as signed bit. So it can use maximum > of 31 bits only. Is this correct? all 32 bits should be safe now. >>>> On a 32 bit machine you will be limited to 16T, this is >>>> actually a page cache limitation. But 2T should be fine. > > Please clarify me that Ext4 is using a 48 bit addressing. Is this > necessary to go for 64 bit machines to utilize Ext4 and manage up to > and including 2TB size file system... Please clarify me. The ext4 ondisk format does use 48 bits for physical addressing, but userspace is still 32 bits only even for ext4. -Eric > Thanks in advance. > > > Regards, Ramesh -- 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
