[Mageia-discuss] Partitioning tools

Fri Jun 10 06:02:59 CEST 2011

David W. Hodgins a écrit :
+>
+> On Thu, 09 Jun 2011 09:33:23 -0400, Doug Lytle <support at drdos.info> wrote:
+>
+>> I've purchased a Hitachi 3TB drive that uses 4k sectors.
+>
+> The drive is using 4k physical sectors. Is it using 512 byte logical
+> sectors or 4k logical sectors?
+>
+> If it's using 4k logical sectors, you don't have to worry about
+> alignment.
+>
+> If it's using 512 byte logical sectors, then you have two things to do.
+>
+> Ensure partitions are aligned on 4k boundaries.
+>
+> Use a gpt partition table, instead of a msdos style partition table,
+> as the msdos partition table cannot address anything beyond 2TB, due
+> to the use of 32 bit sector numbers.
+
+A gpt partition table is also more secure, with a backup table at the end of the disk.
+Gpt typically has 128 partitions, all primary.  Gpt doesn't have secondary partitions, thus 
+avoiding the associated daisy-chaining.  Additionally, a gpt table takes less space than the 
+equivalent mbr format with secondary partitions.
+>
+> I'd use gparted to partition the drive. In gparted, select Device,
+> Create partition table, Advanced, and use the drop down button to
+> select a partition table type of gpt. This creates a msdos style
+> mbr with a fake 2TB partition, so that older partitioning tools
+> like fdisk won't see any free space, and uses the guid partition
+> table to store information about the real partitions. See
+> http://en.wikipedia.org/wiki/GUID_Partition_Table for details.
+>
+> I think gparted will default to aligning the partitions on 1MB
+> boundaries, which is a multiple of 4k.
+
+That is my understanding as well.
+
+> After you've partitioned the drive with gparted, you may be able to
+> use diskdrake to specify the mount points, and create the fstab
+> entries, but I'm not sure if it will work with a gpt partition table,
+> as I've never tried it.
+
+It would be much _safer to simply edit /etc/fstab to change the mount points.  (Creating any 
+corresponding folders as needed.)
+You _could_ use diskdrake to specify the mount points, but it is very risky to do any other changes.
+When I tried some other changes with Mandriva 2010.0, it corrupted the partition table -- every 
+time.  (I didn't realise the cause until I specifically tested for corruption.)
+I had to boot using systemrescuecd, and use gdisk on the cd, to repair the partition table.
+(If you procede carefully, gdisk, now in Mageia, is a useful tool for gpt disks, much like fdisk 
+for mbr disks.)
+
+>
+> Regards, Dave Hodgins
+
+-- 
+André
+