Topic: block size on RAID

[imatt]

cat /proc/mdstat

Personalities : [raid1]
md2 : active raid1 hdc2[1] hda2[0]
      38973568 blocks [2/2] [UU]

md1 : active raid1 hdc1[1] hda1[0]
      104320 blocks [2/2] [UU]

what does the different block sizes mean?

[CharlieBrady]

cat /proc/mdstat

Personalities : [raid1]
md2 : active raid1 hdc2[1] hda2[0]
      38973568 blocks [2/2] [UU]

md1 : active raid1 hdc1[1] hda1[0]
      104320 blocks [2/2] [UU]

what does the different block sizes mean?

There is no different block size. All blocks are the same size (1024 bytes).

You have two partitions, and they are different sizes. /dev/md1 contains /boot and is about 100MB. /dev/md2 contains everything else (about 40GB).

[imatt]

ok, thanks for the reply.

I originally posted the following as the two drives were out of sync.

http://forums.contribs.org/index.php?topic=33910.0

having got them to sync I thought the block size would be the same for both drives as they are now in sync. (Both 40GB)

Could you explain what or why they reflect two different block sizes?

A friend of mine runs SME7 as well and he had the same issue of the two drives neededing 'manual intervention' but followed the above post and his is now in sync.
I have been running a SME since v6 (about 3 yrs now) and still struggle to get my head around this stuff sometimes. Maybe the above post is not right? Sorry if this is a stupid question or if I am off track with this.

[raem]

imatt

It seems like you don't understand what this is telling you.
Your RAID1 array is made of 2 drives hda & hdc
Each drive has 2 partitions md1 & md2
In RAID1 both drives will be partitioned identically as they are "mirrors" of each other.
As Charlie has answered md1 is the boot partition (which I believe has the information needed to tell your system how to start up) & md2 has all the other data (eg directories & files)
[2/2] is telling you that each partition is active & OK & is synchronised with each other

So both drives are present & OK with two partitions of the same size on each drive

cat /proc/mdstat

Personalities : [raid1]
md2 : active raid1 hdc2[1] hda2[0]
      38973568 blocks [2/2] [UU]

md1 : active raid1 hdc1[1] hda1[0]
      104320 blocks [2/2] [UU]

[CharlieBrady]

Could you explain what or why they reflect two different block sizes?

Which part of "there is no different block size" did you not understand?

And which part of "You have two partitions, and they are different sizes" is not clear to you?

[imatt]

OK, Thanks Ray. I did not know that each drive had two partitions. (it makes sense now, /boot and /home)

I also did not know that md1 and md2 were the same drive. I was reading it as md2 having 38973568 blocks and md1 having 104320 blocks, hence me thinking that the two drives had a different (used) block count. sorry.

I now understand how to look at it.

when i said 'Could you explain what or why they reflect two different block sizes? ' i meant (used) block count as I was looking at it as explained above.

Charlie, I am sorry if I offended you with what must seem to you a simple question.

[CharlieBrady]

Charlie, I am sorry if I offended you with what must seem to you a simple question.

The simplicity of the question did not offend me. I was, however, irritated by the fact that you showed no sign of having read and tried to understand my response.

[imatt]

Charlie, I did read your response but at that time the penny had not dropped that md1 and md2 were different partitions and NOT different drives.
This thread has however educated myself and two SME running friends.
Thankyou for your time.