On 2011-08-01 19:49, James wrote: > Sorry for delayed response, I've been reading up > on gpt-fdisk [1]. > Interesting reading on gpt-patch-fdisk....
Thanks for the link; I haven't done such a thorough investigation as you seem to have done... :-) > So "parted" 2.3 in on the minimal cd I'm using: > install-amd64-minimal-20110714.iso > should be as sufficient as gparted? As long as it has support for GPT and 4k-disks it should be sufficient... > If so, it looks like my disk(s) setups > which are identical are ok? [2] seems to Ok or not... do they work as intended? If so I would say they work fine... If you are asking if they are optimised or not I can honestly say: I don't know. Also, if what you are after is an optimised setup for your particular needs then you need to take into account the file system (and, if so required, raid and/or lvm system setup). Which leads this into a whole world of things to work out (workloads/usage patterns)... You need to decide how much time you want to spend on optimising this... Myself, I've given up on that. But since you're doing a raid 1 setup (mirrored) I assume the theoretical limit (i.e. MB/s) would be the individual disks. > suggest that what I originally used (fdisk) > to partition a 4K block drive > (fdisk -H 224 -S 56 -l) will > work, but the drive is NOT optimized? This[*1] seems to suggest that the above fdisk line will create partition aligned to 128k boundaries (excepting the first partition which is aligned to 4k) for SSDs... again, haven't delved into the breadth and depth needed for this to say something with something with authority... :-) [*1] http://www.linuxfoundation.org/news-media/blogs/browse/2009/02/aligning-filesystems-ssd%E2%80%99s-erase-block-size > (parted) print > Model: ATA ST32000542AS (scsi) > Disk /dev/sda: 2000GB > Sector size (logical/physical): 512B/512B ^^^^^^^^^ Hm... this may be an indication that the disks are "lying" to the kernel about it's physical layout, telling it that it's a 512B sector size disk when it's really a 4k sector disk... But I think parted can align correctly anyway... see below Gentoo forum link for details... > Partition Table: msdos ^^^^^ This seems to suggest you are using MBR and not GPT, if that's what you wanted (the size of your disks suggests you don't need GPT - <=2TB is fine with MBR, only with sizes >2TB you need GPT)... I think that parted can change the partition layout to GPT if you really want, but I don't have it installed currently since I used the Gentoo live cd to partition/install so I can't check on which command to perform that. However, a word of caution: If you're trying to boot from a GPT disk then you need (U)EFI firmware as opposed to "regular" bios (I think)... For booting from an GPT disk there are some other hiccups as well, which I've discovered, in that you _may_ need something called an EFI System Partition, which is a VFAT formatted partition which is reserved for the (U)EFI firmware (my system wouldn't boot without it - although I'm using an SASWT4I "fake" raid card from Intel and GRUB2, which may have complicated things...). > Number Start End Size Type File system Flags > 1 1049kB 269MB 268MB primary boot, raid > 2 269MB 5414MB 5144MB primary raid > 3 5414MB 2000GB 1995GB primary raid > > and > (parted) align-check minimal 1 > 1 aligned > (parted) align-check optimal 1 > 1 aligned > (parted) align-check optimal 2 > 2 aligned > (parted) align-check optimal 3 > 3 aligned > (parted) Hm... afaik the alignment issue is digital; either it's aligned (to 4k or whatever) or it's not... as long as the tool used can handle it there shouldn't be any differences (fdisk/gdisk/parted). That said, I think that parted always issues the "aligned" message when doing the align-check command (assuming it was succesfull) so you can't judge if any previous attempts was succesful or not (I think that's what you were trying to do if I understand you correctly). > Should I conclude that sda and sdb are > correct and optimized for 4K block drives? Perhaps this may help (I don't have any 4k sector disks so...): http://forums.gentoo.org/viewtopic-t-838522-start-0.html > I never used parted before, so I can easily be making > a mistake [3] or poor assumption? Hm... the only way to be sure is to test it ( or "nuke it from above" ;-) ). I hope I have (accidentally or not) made some sense... :-D Best regards Peter K
