On 08/12/2013 12:21 PM, John R Pierce wrote: > ... and MBR disks have an absolute maximum size of 2TB
Actually, no. The size of disk usable in an MBR partitioning scheme is dependent upon the disk's block size; with 4k blocks MBR can (and does) go above 2TB. We actually have a pair of Western Digital 3TB externals that are NTFS-formatted and MBR partitioned. Yes, this is non-standard and breaks the 'letter' of the MBR specs, but, it works fine on Windows, which is the target audience. The Mac-formatted Studio drives are GPT partitioned (and cost more). The Linux HFS and HFS+ filesystem drivers don't like the 3TB HFS+ formatted WD Studio 3TB I have here, either...... see: http://forums.anandtech.com/archive/index.php/t-2174705.html and the comment by Mark R down the page a bit. Seagate and WD both do this with external 3TB drives meant for PCs. WD does something very similar for their MyBookLive models; these units are the network-attached ones, and 3TB single-drive and 6TB dual-drive units are common. The NAS embedded OS is Linux, and the main data partition is formatted 64k-blocksize ext4: (This is on a 1TB model....) LOMBL1:~# df -h Filesystem Size Used Avail Use% Mounted on /dev/md0 1.9G 541M 1.3G 30% / tmpfs 5.0M 0 5.0M 0% /lib/init/rw udev 10M 6.7M 3.4M 67% /dev tmpfs 5.0M 0 5.0M 0% /dev/shm tmpfs 100M 10M 90M 10% /tmp ramlog-tmpfs 20M 3.4M 17M 17% /var/log /dev/sda4 924G 922G 2.5G 100% /DataVolume LOMBL1:~# tune2fs -l /dev/sda4 tune2fs 1.41.12 (17-May-2010) Filesystem volume name: <none> Last mounted on: /CacheVolume Filesystem UUID: 2631203b-3cb5-4f63-b9ae-12fed7e5d0bd Filesystem magic number: 0xEF53 Filesystem revision #: 1 (dynamic) Filesystem features: has_journal ext_attr resize_inode dir_index filetype needs_recovery extent flex_bg sparse_super large_file huge_file uninit_bg dir_nlink extra_isize Filesystem flags: unsigned_directory_hash Default mount options: (none) Filesystem state: clean Errors behavior: Continue Filesystem OS type: Linux Inode count: 15144960 Block count: 15191355 Reserved block count: 0 Free blocks: 892140 Free inodes: 14734611 First block: 0 Block size: 65536 Fragment size: 65536 Reserved GDT blocks: 32 Blocks per group: 65528 Fragments per group: 65528 Inodes per group: 65280 Inode blocks per group: 255 Flex block group size: 16 Filesystem created: Thu Apr 7 19:26:05 2011 Last mount time: Tue Jun 4 16:02:59 2013 Last write time: Tue Jun 4 16:02:59 2013 Mount count: 15 Maximum mount count: 29 Last checked: Thu Apr 7 19:26:05 2011 Check interval: 15552000 (6 months) Next check after: Tue Oct 4 19:26:05 2011 Lifetime writes: 1173 GB Reserved blocks uid: 0 (user root) Reserved blocks gid: 0 (group root) First inode: 11 Inode size: 256 Required extra isize: 28 Desired extra isize: 28 Journal inode: 8 Default directory hash: half_md4 Directory Hash Seed: 4a2c0236-2d62-4779-bb5b-950094980616 Journal backup: inode blocks LOMBL1:~# LOMBL1:~# parted /dev/sda print Model: ATA WDC WD10EACS-00Z (scsi) Disk /dev/sda: 1000GB Sector size (logical/physical): 512B/512B Partition Table: gpt Number Start End Size File system Name Flags 3 15.7MB 528MB 513MB linux-swap(v1) primary 1 528MB 2576MB 2048MB ext3 primary raid 2 2576MB 4624MB 2048MB ext3 primary raid 4 4624MB 1000GB 996GB ext4 Microsoft basic data LOMBL1:~# cat /etc/debian_version 5.0.4 LOMBL1:~# uname -a Linux LOMBL1 2.6.32.11-svn70860 #1 Thu May 17 13:32:51 PDT 2012 ppc GNU/Linux LOMBL1:~# Oh, but 64k blocksize ext4 is NOT supported on almost all PC linux distributions, including CentOS..... At least it's not a funky MBR format, and GPT is used.... And yet the MyBookLive runs Debian 5.0.4/PPC...... Go figure. For more info on the MyBookLive from a linux point of view, see http://mybookworld.wikidot.com/ (it's a fun box to play with, and much more robust than the previous 'World Edition' drives). CentOS works fine with the SMB shares the MBL exports, and I'm using one right for backups. _______________________________________________ CentOS mailing list CentOS@centos.org http://lists.centos.org/mailman/listinfo/centos
