Arch Linux

whoops

Member

Registered: 2009-03-19

Posts: 891

SoftRaid0: 1 of 3 md's no speed enhancment (using logical partitions)?

Hi!

Before I forget to mention it: I don't really know much about raid & stuff (I'm surprised myself I got it running), so don't think a possible explanations is too obvious/simple - I might have missed it anyway

I've got 3 (+ backup) Raid0's on the same 2 sata hd's. The first two seem to work with the right speed, the third one only normal / half of it. The only difference I could find is that md2 consists of logical partitions - md0 and md1 have their own primary partition each.

All in infos in order md0/1/2

/dev/md0 partition    3999992    76416   -1 (<= cat /proc/swaps)
/dev/md1 on /home type ext4 (rw)
/dev/md2 on / type ext4 (rw)

/dev/md0: 3.81GiB raid0 2 devices, 0 spares.
/dev/md1: 889.97GiB raid0 2 devices, 0 spares.
/dev/md2: 18.63GiB raid0 2 devices, 0 spares.

 Timing buffered disk reads:  446 MB in  3.01 seconds = 148.08 MB/sec
 Timing buffered disk reads:  470 MB in  3.01 seconds = 156.20 MB/sec
 Timing buffered disk reads:  234 MB in  3.02 seconds =  77.57 MB/sec

    Number   Major   Minor   RaidDevice State
       0       8        2        0      active sync   /dev/sda2
       1       8       18        1      active sync   /dev/sdb2
    Number   Major   Minor   RaidDevice State
       0       8        3        0      active sync   /dev/sda3
       1       8       19        1      active sync   /dev/sdb3
    Number   Major   Minor   RaidDevice State
       0       8        5        0      active sync   /dev/sda5
       1       8       21        1      active sync   /dev/sdb5

sda & sdb look the same:

/dev/sda1   *           1          31      248976   83  Linux
/dev/sda2              32         280     2000092+  fd  Linux raid autodetect
/dev/sda3             281       58369   466599892+  fd  Linux raid autodetect
/dev/sda4           58370       60801    19535040    5  Extended
/dev/sda5           58370       59585     9767488+  fd  Linux raid autodetect
/dev/sda6           59586       60801     9767488+  fd  Linux raid autodetect

sd*6 (sometimes md3) is a spare raid that shares the same extended partition - and low speed. Most of the time it is not assembled though, which doesn't change anything for md2.

Any Ideas?

whoops

Member

Registered: 2009-03-19

Posts: 891

Re: SoftRaid0: 1 of 3 md's no speed enhancment (using logical partitions)?

Still the same, didn't manage to figure anything more out about that.

Could someone with Extended soft-raid maybe just confirm, if
a) It's the same as with my "slow partition"
b) It's also possible to be "fast"
?

Or something... anything?

thx!