On 1 Mar 2013 at 14:46, Saifi Khan wrote: > On Sat, 23 Feb 2013, David Lord wrote: > > > On 23 Feb 2013 at 20:18, Saifi Khan wrote: > > > >> Hi: > >> > >> Please excuse me for asking rather 'naive' question. > >> > >> i've rtfm'd at > >> http://www.netbsd.org/docs/guide/en/netbsd.html > >> > >> Now, i have a boot disk (NetBSD terminology) of 320 GB (SATA II). > >> > >> Booted my laptop with 'boot.iso' (NetBSD-current) and using the 'NetBSD' > >> fdisk utility, i created two MBR partitions (NetBSD terminology) of the > >> following size: > >> partition no 1: 20 GB (base system, src) > >> partition no 2: 300 GB (pkgsrc, other sources, mails etc.) > >> > >> i intend to setup 'ffs' on both the MBR partitions. > >> > >> in the linux world, the disk would typically be '/dev/sda' and the two > >> profound partitions would be > >> /dev/sda1 > >> /dev/sda2 > >> > >> in the NetBSD scheme of things, the first disk is seen as 'wd0'. In that > >> case, how would the two 'MBR partitions' be addressed as ? > >> > > > > The NetBSD part of the disk is usually split into partitions > > > > ID mount point > > a: / > > b: swap > > c: NetBSD partitions > > d: whole disk > > e: /usr > > f: /tmp > > g: /var > > .... > > m: > > > > The 'mbrlabel' command helped insert the 2nd MBR partition > entry in the disklabel. > > However, the wrong size was picked by mbrlabel (wonder why) > and i had to edit the 'disklabel' entry from the information > gleaned from 'fdisk' output. > > > > Having many mountable partitions used to have an advantage > > after a major system crash in that some would be left clean > > which reduced time spent by fsck. With current WAPBL the > > journal is replayed after a crash which gives a fast > > recovery. > > > > Does disk geometry, the CHS remapping and subsequent > translation have any impact on the 'fsck' performance. ?
Probably but I don't run fsck so often that it concerns me. > > > >> i also have a couple of related questions: > >> > >> 1. what is the rationale behind using 'd' in BSD partition to represent > >> the entire disk ? > >> 2. what is the significance of using two representations like wd0 and rwd0 > >> ? > > > > The 'raw' devices have to be used in some cases but unless > > you are sure use the 'wd" rather than "rwd". > > > > Would appreciate, if you could share an example where 'raw' > device would be useful. > This is something that usally appears in the relevant man page for the program you are using. > > >> 3. does fsck like utility perform better when one has slice with BSD > >> partitions rather than straight DOS like partition ? > > > > DOS fat partitions become fragmented and can run out of > > allocation units so require regular defragmentation as the > > partition becomes full. > > > > Fsck is not normally required on NetBSD ffs partitions. > > > > currently running netbsd-current (20120220 snapshot). > > i have had two freeze ups in the last 2 days, when i had to > hold the 'power' button to switch off the laptop. > > On power cycling the device, on both occassions, i had to > run 'fsck' manually to restore blocks, clean up etc. > I's rare for me to need to use fsck. After a crash requiring reboot I see entries in /var/log/messages: "/netbsd: /: replaying log to disk" Were your partitions created manually? Currently my systems have ffsv2 partitions either auto created at install, using "newfs -O", or by using "ffsk_ffs -c 4" for existing partitions. /etc/fstab entries have the "log" option, eg. /dev/wd0a / ffs rw,log 1 1 /dev/wd0h /var ffs rw,log 1 2 David
