I am new to this and was wondering if someone could help me out. I have Ubuntu 12.04 installed on a custom built computer. I have a RAID 0 setup across 2 160 GB disks (512 sector size). I have been thinking that my system is not performing as well as it should be lately. When I apply the system updates, they are now taking an extended length of time to complete (up to 20-30 mins).
I am thinking the problem is I/O related as it's things like updates which give me the most grief (slowing the system to a crawl and top is not showing high levels of memory/CPU utilization).
I have done some digging and found some curious items in my partition tables. sfdisk is showing two empty partions (gparted complains about partitions not on the disk):
kbarlow@atlantia:/home/kbarlow$ sudo sfdisk -d /dev/mapper/isw_cacihdigbh_Volume0
Warning: extended partition does not start at a cylinder boundary.
DOS and Linux will interpret the contents differently.
# partition table of /dev/mapper/isw_cacihdigbh_Volume0
/dev/mapper/isw_cacihdigbh_Volume0p1 : start= 512, size=599995392, Id=83, bootable
/dev/mapper/isw_cacihdigbh_Volume0p2 : start=599996416, size= 25157632, Id= 5
/dev/mapper/isw_cacihdigbh_Volume0p3 : start= 0, size= 0, Id= 0
/dev/mapper/isw_cacihdigbh_Volume0p4 : start= 0, size= 0, Id= 0
/dev/mapper/isw_cacihdigbh_Volume0p5 : start=599998464, size= 25155584, Id=82
also, fdisk doesn't show these partitions but shows some weird values for I/O size:
kbarlow@atlantia:/home/kbarlow$ sudo fdisk -l /dev/mapper/isw_cacihdigbh_Volume0
Disk /dev/mapper/isw_cacihdigbh_Volume0: 320.1 GB, 320079134720 bytes
255 heads, 63 sectors/track, 38914 cylinders, total 625154560 sectors
Units = sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 131072 bytes / 262144 bytes
Disk identifier: 0x0007c90a
Device Boot Start End Blocks Id System
/dev/mapper/isw_cacihdigbh_Volume0p1 * 512 599995903 299997696 83 Linux
/dev/mapper/isw_cacihdigbh_Volume0p2 599996416 625154047 12578816 5 Extended
/dev/mapper/isw_cacihdigbh_Volume0p5 599998464 625154047 12577792 82 Linux swap / Solaris
Looking at this link http://www.linuxquestions.org/questi...e-disk-865616/
I think I should be able to simply delete the two empty partitions (I think the installer had some difficulties when setting up the partitioning structure). However, I am wondering if I have a misconfiguration with respect to the I/O size values... most of the samples I see that people have posted appear to have I/O sizes set to 512 or 4096 (advanced formatting). I don't know if these values are to be expected because of the RAID 0 configuration or what... Can anyone shed some light on this?