I went through this exercise to determine if there were boundary issues installing FreeBSD on disks. I concluded that FreeBSD was indeed installing at head boundaries. A colleague then pointed me to http://ivoras.net/blog/tree/2011-01-01.freebsd-on-4k-sector-drives.html which calls into question whether sysinstall and fdisk really are installing FreeBSD's slice at the 64th cylinder. Should I be concerned with this?
This came about due to a scenario where Linux would start its filesystem at sector 63, right before the head boundary. On I/O intensive applications, it was common for reads/write to cross the head boundary resulting in unnecessary disk thrashing and long I/O wait times. The issue was corrected in Linux by changing the start cylinder to 2048. Some theorized that FreeBSD was vulnerable to this scenario. Thoughts/feedback? On Fri, Jul 6, 2012 at 11:09 AM, Rick Miller <vmil...@hostileadmin.com> wrote: > Hi All, > > Installing FreeBSD 8.x I select "A" at the fdisk partition editor to > use the entire disk. It creates an unused slice with offset 0 and 63 > sectors in size. Then partition 1 starts at sector 63 and utilizes > the remaining disk space. Does sysinstall's diskPartitonEditor macro > automatically start partitions at head boundaries? The reason I ask > is because I am most familiar with sector 64 being the start of a head > boundary as opposed to 63. Is my understanding incorrect? > > -- > Take care > Rick Miller -- Take care Rick Miller _______________________________________________ freebsd-questions@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-questions To unsubscribe, send any mail to "freebsd-questions-unsubscr...@freebsd.org"
