Topic: DegradedArray on single disk

[electroman00]

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[Stefano]

if ide channel fails, your data is gone..  Maybe

having 2 hd in raid1 on a single ide channel and a failure on that channel is data corruption at 99%
and, of course, 2 hds on the same ide channel are not the best choice for speed.

hd MUST can be on different channels and preferably as master on both channels.. or on the same channel.

if we are talking about test server or home server, ok.
hd can be different by size, type, everything..
but I think we are talking about production server with valuable data..

Some day you'll realize nothing is absolute except for death and taxes...!!

I've already realized it.. don't worry

Well maybe we can add one more, the world absolutely didn't need George W Bush.

this is a bit OT, but I agree 1000%

Ciao
Stefano

[electroman00]

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[Agent86]

Hi

I have 2) disks on ATA IDE separate cables

I've been reading about the Soft RAID messages and what they mean and would like to ask for confirmation about this:

I recently got a degraded array message.

My RAID says:

Current RAID status:                               
  │                                                                         
  │ Personalities : [raid1]                                                 
  │ md1 : active raid1 hda1[0] hdc1[1]                             
  │       104320 blocks [2/2] [UU]                                           
  │ md2 : active raid1 hdc2[1]                                               
  │       59947136 blocks [2/1] [_U]                                         
  │ unused devices: <none>                                                   
  │                                                                         
  │                                                                         
  │ Only some of the RAID devices are unclean.                             
  │                                                                       
  │ Manual intervention may be required. 

Am I correct to say that (hdc2) is my problem drive and should be replaced ?

From what I read the [UU] means both are alive, however if both are alive I'm not sure how to interpret the second drive saying [_U] ? Does that mean it's down ?

Please advise ? Thanks

[Stefano]

Am I correct to say that (hdc2) is my problem drive and should be replaced ?

no.. hdc(1,2) is the good one.. hda has a problem..

check your /var/log/messages and search for hda2

HTH
Ciao
Stefano

[electroman00]

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[Tillebeck]

electroman00, you wrote:

md2 partition on hda failed, notice hda1[0] is missing on md2

It should be hda2[0] that is missing from md2, right?

[electroman00]

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[Agent86]

I'm not sure I understand this

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

Shows both drives sync'd on the md1 partion.

I only have 2) drives so how can both drives sync'd on md1 partition ?

But I think I do understand this now so hda2[0] has failed which is the md2 [_U] underscore showing failed. But is this a failed partition or drive ? Or does it mean the same thing ?

Am I understanding this correctly md1 showing 2/2 partitions, and md2 showing 2/1 meaning 1 of 2 partitions ?

Thanks for all the help. Sorry I'm having trouble understanding this.

[electroman00]

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[Agent86]

electroman00- Yes I have CD rom on the primary slave

I'm getting confused about this.
How can hda1[0] show as sync'd but hda2[0] is missing, isn't hda1[0] mirroring to hda2[0] which is missing or failed ?

I thought that the first drive hda with 2 partitions was mirroring or duplicated to hdc with the same 2 partitions ?

Please excuse my ignorance

Also I'll run those Disk Health tests you linked to and post back on that also.
Thanks

[electroman00]

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[electroman00]

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[electroman00]

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[pfloor]

I'm not sure I understand this

I only have 2) drives so how can both drives sync'd on md1 partition ?

But I think I do understand this now so hda2[0] has failed which is the md2 [_U] underscore showing failed. But is this a failed partition or drive ? Or does it mean the same thing ?

Am I understanding this correctly md1 showing 2/2 partitions, and md2 showing 2/1 meaning 1 of 2 partitions ?

Thanks for all the help. Sorry I'm having trouble understanding this.

You are confusing the differences between drives, partitions and raid devices.  For simplicity, we will use your setup as the example here.

Think of it this way:

-hda and hdc are drives
-hdaX and hdcX are partitions
-md1 and md2 are raid devices

Two or more drives can be mirrored together to construct a raid device (SME does NOT use this concept).

Two or more partition can be mirrored together to construct a raid device (this is how SME is configured).

In your SME configuration:
-Partition hda1 and partition hdc1 are mirrored together to construct a raid device called md1
-Partition hda2 and partition hdc2 are mirrored together to construct a raid device called md2

A raid device can still operate with only 1 partition active.  Your machine is doing this:

hda1 + hdc1 = md1
<non working partition> + hdc2 = md2

Your machine has 1 partition (hda2) that is out of sync, not an entire drive.  You still have your original 2 raid devices (md1 and md2) working but md2 does not have redundancy any more so if hdc (or hdc2) goes bad, you will lose your data.

Is hda2 bad??? most likely not. There are a few things I have learned over the years.

1-Cheap cables cause raid devices to go out of sync, always use high quality 80 wire cables.
2-Cheap power supplies cause raid devices to go out of sync, always use good power supplies.
3-Bad memory can causes sync issues, check your memory.
4-Power spikes and sags cause raid devices to go out of sync, ALWAYS use battery backups to keep the power level constant.
5-IBM (now Hitachi) IDE drives don't stay in sync well.  Don't use them.