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Failed Redundancy



 
 
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  #1  
Old January 3rd 18, 08:27 AM posted to alt.comp.os.windows-10
Tim[_10_]
external usenet poster
 
Posts: 63
Default Failed Redundancy

First off - Windows 10 1709 fully patched.

I have two 2TB disks in a Windows software Raid 1 array. They are
initialized as Dynamic. The last time I looked at Disk Management it
informed me that they had 'Failed Redundancy'. I have a pretty good idea of
what that means, but I can't find anywhere where it tells me what I should
do about it. Anytime I look on line it starts giving examples and fixes for
Windows Server 2012, which doesn't do me a lot of good.

What exactly does 'Failed Redundancy' mean. I know it means they are no
longer in sync, but does it mean the system is writing to one and not the
other? Or that at one time a write didn't take place to one of the pair,
and now Windows can't guarantee that everything is exact? If Windows is
only writing to one, which one? Is there something I can diagnose that will
help me figure out what is going on?

I know that worst case I can back up the drive(s) to another disk, break
the Raid, reinitialize both drives after testing the hell out of them, then
reload the backup and hope everything is ok. Since backing up the drive to
an external disk takes about 16hrs, I would rather not take that path. Do I
have any other options?
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  #2  
Old January 3rd 18, 08:54 AM posted to alt.comp.os.windows-10
Paul[_32_]
external usenet poster
 
Posts: 4,879
Default Failed Redundancy

Tim wrote:
First off - Windows 10 1709 fully patched.

I have two 2TB disks in a Windows software Raid 1 array. They are
initialized as Dynamic. The last time I looked at Disk Management it
informed me that they had 'Failed Redundancy'. I have a pretty good idea of
what that means, but I can't find anywhere where it tells me what I should
do about it. Anytime I look on line it starts giving examples and fixes for
Windows Server 2012, which doesn't do me a lot of good.

What exactly does 'Failed Redundancy' mean. I know it means they are no
longer in sync, but does it mean the system is writing to one and not the
other? Or that at one time a write didn't take place to one of the pair,
and now Windows can't guarantee that everything is exact? If Windows is
only writing to one, which one? Is there something I can diagnose that will
help me figure out what is going on?

I know that worst case I can back up the drive(s) to another disk, break
the Raid, reinitialize both drives after testing the hell out of them, then
reload the backup and hope everything is ok. Since backing up the drive to
an external disk takes about 16hrs, I would rather not take that path. Do I
have any other options?


How about this one.

Apparently uses Disk Management window.

https://technet.microsoft.com/en-us/.../ff601861.aspx

Paul
  #3  
Old January 4th 18, 06:47 AM posted to alt.comp.os.windows-10
Tim[_10_]
external usenet poster
 
Posts: 63
Default Failed Redundancy

Paul wrote in news

How about this one.

Apparently uses Disk Management window.

https://technet.microsoft.com/en-us/.../ff601861.aspx

Paul

I had looked at that before. None of the four situations apply to my
drives. I did to a 'resyncronize' just now and it failed.

I have another 2tb drive I bought to replace an older drive that failed,
that I haven't installed yet. I was thinking install that drive. Initialize
it GPT like the other two, and see if I can add it to the mirror. If that
works I can remove one of the other drives from the mirror, reinit it, and
add it back to the mirror. That will give me two good drives again in a
RAID 1, and I can reinit the last one and use it to replace the other
failed drive.

If that doesn't work, I will back up the RAID drive to the new disk,
totally destroy the existing raid, and create a new one.

Are either of these to ideas feasible?
  #4  
Old January 4th 18, 07:58 AM posted to alt.comp.os.windows-10
Char Jackson
external usenet poster
 
Posts: 8,944
Default Failed Redundancy

On Thu, 04 Jan 2018 05:47:29 GMT, Tim wrote:

I have another 2tb drive I bought to replace an older drive that failed,
that I haven't installed yet. I was thinking install that drive. Initialize
it GPT like the other two, and see if I can add it to the mirror. If that
works I can remove one of the other drives from the mirror, reinit it, and
add it back to the mirror. That will give me two good drives again in a
RAID 1, and I can reinit the last one and use it to replace the other
failed drive.

If that doesn't work, I will back up the RAID drive to the new disk,
totally destroy the existing raid, and create a new one.


Just curious, what are your goals for using RAID 1? I've tried a few
RAID implementations over the years and always abandoned them rather
quickly. Most were simply too much trouble, too fragile, or too slow
(read, write, or both).

Other than this current failure, how has it been working for you?

  #5  
Old January 4th 18, 07:58 AM posted to alt.comp.os.windows-10
Paul[_32_]
external usenet poster
 
Posts: 4,879
Default Failed Redundancy

Tim wrote:
Paul wrote in news
How about this one.

Apparently uses Disk Management window.

https://technet.microsoft.com/en-us/.../ff601861.aspx

Paul

I had looked at that before. None of the four situations apply to my
drives. I did to a 'resyncronize' just now and it failed.

I have another 2tb drive I bought to replace an older drive that failed,
that I haven't installed yet. I was thinking install that drive. Initialize
it GPT like the other two, and see if I can add it to the mirror. If that
works I can remove one of the other drives from the mirror, reinit it, and
add it back to the mirror. That will give me two good drives again in a
RAID 1, and I can reinit the last one and use it to replace the other
failed drive.

If that doesn't work, I will back up the RAID drive to the new disk,
totally destroy the existing raid, and create a new one.

Are either of these to ideas feasible?


You will back up the RAID drive *period*. End of story.

Running a RAID mirror, is not a backup. A backup is
data you place on a third drive. Once the 2TB of data
is on the third drive, now you have a measure of
redundancy you can actually use.

What you do after that, is a carefree experiment. Put
the data some place safe.

Always have *a couple* drives handy for recovery work. *Always*.
Never go into a crisis, half equipped. Make sure the data
is safe first. Then you can make a new drive GPT, and
make it a member of the array, and rebuild (resync).
And see if from a status point of view, it returns
to normal.

I am not a great fan of RAID, because it requires that
the user learn how to use it, in advance. You should
simulate failures as best you can, when setting up the
RAID array. I've done that a couple times as part of
trying to help people with RAID problems. Trying to
wing it later, is inevitable, and you can't test every
possible scenario, but I find you can do enough tests
to get a feeling for what the failures look like, and
what works. Just unplugging a SATA drive, or starting
the machine with one SATA drive connected during boot,
is enough to give a Failed Redundancy message. Doing the
resynchronize at that point, the good drive (whose status
logs what happened) will resync to the "out of sync" one.

To accelerate testing, I've used an HPA to "clip" the capacity
of a drive, so filling the disk is a lot faster. Putting
2TB of data on a 2TB drive would be boring. I clipped
down some drives to 4GB and 6GB, and used those for
some experiments before unclipping them again. HPA
is Host Protected Area. My SATA ports cannot be used
for this (BIOS security feature prevents it). My
JMicron IDE port, with an IDE to SATA adapter on
the end of it, works just fine for defining an HPA.
Once an HPA is set, I can make "tiny" hard drives
for quicker SATA RAID test cases. You can only
execute one HPA command per boot session, and it
takes a lot of reboots to do stuff. The HPA commands
are trap doored. Only one command per session, on
my Jmicron. On the Intel SATA ports, Intel burned up
the single command, such that a user cannot issue
any such commands. The purpose of making the drive
small, is so when the RAID software checks the drive
capacity, it sees a 6GB drive, not a 2TB drive,
as I've clipped off most of the top of the drive
with the HPA. The capacity reads as 6GB when the
software/OS checks it.

After a RAID experiment, I connect the SATA drive
to an older computer, and use diskpart to "clean all".
For hardware RAID, clean all won't clean all of the
disk. You have to arrange things, in the case of
hardware RAID, so the RAID metadata areas are exposed,
so you can erase them. Even erasing from Linux is
not foolproof, as sometimes Linux tries to read
the metadata and make it work as it did in Windows.
When I work with a drive, the drive must be
completely clean, as I have had cases where a
later experiment is ruined, because the test
case can "sniff" the metadata from a previous
experiment.

Paul
  #6  
Old January 4th 18, 05:06 PM posted to alt.comp.os.windows-10
Ken Blake[_5_]
external usenet poster
 
Posts: 1,417
Default Failed Redundancy

On Thu, 04 Jan 2018 00:58:01 -0600, Char Jackson
wrote:


On Thu, 04 Jan 2018 05:47:29 GMT, Tim wrote:


I have another 2tb drive I bought to replace an older drive that failed,
that I haven't installed yet. I was thinking install that drive. Initialize
it GPT like the other two, and see if I can add it to the mirror. If that
works I can remove one of the other drives from the mirror, reinit it, and
add it back to the mirror. That will give me two good drives again in a
RAID 1, and I can reinit the last one and use it to replace the other
failed drive.

If that doesn't work, I will back up the RAID drive to the new disk,
totally destroy the existing raid, and create a new one.


Just curious, what are your goals for using RAID 1? I've tried a few
RAID implementations over the years and always abandoned them rather
quickly. Most were simply too much trouble, too fragile, or too slow
(read, write, or both).

Other than this current failure, how has it been working for you?



Here's my standard post on the subject:

RAID 1 (mirroring) is *not* a backup solution. RAID 1 uses two or
more drives, each a duplicate of the others, to provide redundancy,
not backup. It's used in situations (almost always within
corporations, not in homes) where any downtown can't be tolerated,
because the way it works is that if one drive fails the other takes
over seamlessly.

Although some people thing of RAID 1 as a backup technique, that is
*not* what it is, since it's subject to simultaneous loss of the
original and the mirror to many of the most common dangers threatening
your data--severe power glitches, nearby lightning strikes, virus
attacks, theft of the computer, etc. Most companies that use RAID 1
also have a strong external backup plan in place.

"Why RAID is (usually) a Terrible Idea"
http://www.pugetsystems.com/articles?&id=29

  #7  
Old January 4th 18, 05:56 PM posted to alt.comp.os.windows-10
Char Jackson
external usenet poster
 
Posts: 8,944
Default Failed Redundancy

On Thu, 04 Jan 2018 09:06:40 -0700, Ken Blake
wrote:

On Thu, 04 Jan 2018 00:58:01 -0600, Char Jackson
wrote:

On Thu, 04 Jan 2018 05:47:29 GMT, Tim wrote:

I have another 2tb drive I bought to replace an older drive that failed,
that I haven't installed yet. I was thinking install that drive. Initialize
it GPT like the other two, and see if I can add it to the mirror. If that
works I can remove one of the other drives from the mirror, reinit it, and
add it back to the mirror. That will give me two good drives again in a
RAID 1, and I can reinit the last one and use it to replace the other
failed drive.

If that doesn't work, I will back up the RAID drive to the new disk,
totally destroy the existing raid, and create a new one.


Just curious, what are your goals for using RAID 1? I've tried a few
RAID implementations over the years and always abandoned them rather
quickly. Most were simply too much trouble, too fragile, or too slow
(read, write, or both).

Other than this current failure, how has it been working for you?



Here's my standard post on the subject:

RAID 1 (mirroring) is *not* a backup solution. RAID 1 uses two or
more drives, each a duplicate of the others, to provide redundancy,
not backup. It's used in situations (almost always within
corporations, not in homes) where any downtown can't be tolerated,
because the way it works is that if one drive fails the other takes
over seamlessly.

Although some people thing of RAID 1 as a backup technique, that is
*not* what it is, since it's subject to simultaneous loss of the
original and the mirror to many of the most common dangers threatening
your data--severe power glitches, nearby lightning strikes, virus
attacks, theft of the computer, etc. Most companies that use RAID 1
also have a strong external backup plan in place.

"Why RAID is (usually) a Terrible Idea"
http://www.pugetsystems.com/articles?&id=29


Hi Ken. I agree with you, which is why I'm gently poking around in the
first place. I suspect that the OP perceives a benefit where one might
not exist, but I'm willing to listen. I have no plans to repeat my RAID
experiments here.

  #8  
Old January 4th 18, 09:39 PM posted to alt.comp.os.windows-10
Ken Blake[_5_]
external usenet poster
 
Posts: 1,417
Default Failed Redundancy

On Thu, 04 Jan 2018 10:56:58 -0600, Char Jackson
wrote:


On Thu, 04 Jan 2018 09:06:40 -0700, Ken Blake
wrote:


On Thu, 04 Jan 2018 00:58:01 -0600, Char Jackson
wrote:


On Thu, 04 Jan 2018 05:47:29 GMT, Tim wrote:

I have another 2tb drive I bought to replace an older drive that failed,
that I haven't installed yet. I was thinking install that drive. Initialize
it GPT like the other two, and see if I can add it to the mirror. If that
works I can remove one of the other drives from the mirror, reinit it, and
add it back to the mirror. That will give me two good drives again in a
RAID 1, and I can reinit the last one and use it to replace the other
failed drive.

If that doesn't work, I will back up the RAID drive to the new disk,
totally destroy the existing raid, and create a new one.

Just curious, what are your goals for using RAID 1? I've tried a few
RAID implementations over the years and always abandoned them rather
quickly. Most were simply too much trouble, too fragile, or too slow
(read, write, or both).

Other than this current failure, how has it been working for you?



Here's my standard post on the subject:

RAID 1 (mirroring) is *not* a backup solution. RAID 1 uses two or
more drives, each a duplicate of the others, to provide redundancy,
not backup. It's used in situations (almost always within
corporations, not in homes) where any downtown can't be tolerated,
because the way it works is that if one drive fails the other takes
over seamlessly.

Although some people thing of RAID 1 as a backup technique, that is
*not* what it is, since it's subject to simultaneous loss of the
original and the mirror to many of the most common dangers threatening
your data--severe power glitches, nearby lightning strikes, virus
attacks, theft of the computer, etc. Most companies that use RAID 1
also have a strong external backup plan in place.

"Why RAID is (usually) a Terrible Idea"
http://www.pugetsystems.com/articles?&id=29


Hi Ken. I agree with you,



Yes, you made that clear in your earlier message. My post was meant
for the OP, not for you.



which is why I'm gently poking around in the
first place. I suspect that the OP perceives a benefit where one might
not exist, but I'm willing to listen. I have no plans to repeat my RAID
experiments here.

  #9  
Old January 5th 18, 02:08 AM posted to alt.comp.os.windows-10
Tim[_10_]
external usenet poster
 
Posts: 63
Default Failed Redundancy

Char Jackson wrote in
:

Just curious, what are your goals for using RAID 1? I've tried a few
RAID implementations over the years and always abandoned them rather
quickly. Most were simply too much trouble, too fragile, or too slow
(read, write, or both).

Other than this current failure, how has it been working for you?


This RAID configuration has run just fine for four years, since I set the
system up in 2013. I use it because I don't keep anything but system files
on my system drive, and all of my collected files and personal data are on
this RAID drive. I have had no performance issues, mainly because my system
drive is SSD, so those programs and files just snap right in.
  #10  
Old January 5th 18, 02:19 AM posted to alt.comp.os.windows-10
Tim[_10_]
external usenet poster
 
Posts: 63
Default Failed Redundancy

Ken Blake wrote in
:



Here's my standard post on the subject:

RAID 1 (mirroring) is *not* a backup solution. RAID 1 uses two or
more drives, each a duplicate of the others, to provide redundancy,
not backup. It's used in situations (almost always within
corporations, not in homes) where any downtown can't be tolerated,
because the way it works is that if one drive fails the other takes
over seamlessly.

Although some people thing of RAID 1 as a backup technique, that is
*not* what it is, since it's subject to simultaneous loss of the
original and the mirror to many of the most common dangers threatening
your data--severe power glitches, nearby lightning strikes, virus
attacks, theft of the computer, etc. Most companies that use RAID 1
also have a strong external backup plan in place.

"Why RAID is (usually) a Terrible Idea"
http://www.pugetsystems.com/articles?&id=29

Attachment decoded: untitled-1.txt


I don't use it as a backup per se. I have two external drives I alternate
as backup drives periodically. My thinking is more that the most common
fault I would probably suffer would be a disk failure. If that happens
than the other drive in the pair will still have my data, and I can
quickly run another backup, then fix/replace the failing drive.

Lately I have been reconsidering that philosophy. As the way all things
go, I now have more than 2TB of data saved. Rather than set up another
pair and another set of backup drives, I am seriously considering
obtaining a larger (4TB+) external drive, and set things up as a kind of
continuous backup. The software Western Digital provides with their
drives offers as an option mirroring changes to a source drive to a
secondary drive. That drive, while available in File Explorer, would not
be in active use, but would be a 'dynamic' backup. I would still backup
periodically to my current external drives, but wouldn't have the
overhead of the software RAID, and could probably do a better job of
distributing my data across my drives.

Oh, and I have an APS UPS to help protect agains power failures, surges,
and nasty noise on the power lines.
  #11  
Old January 5th 18, 02:33 AM posted to alt.comp.os.windows-10
Tim[_10_]
external usenet poster
 
Posts: 63
Default Failed Redundancy

Paul wrote in news
After a RAID experiment, I connect the SATA drive
to an older computer, and use diskpart to "clean all".
For hardware RAID, clean all won't clean all of the
disk. You have to arrange things, in the case of
hardware RAID, so the RAID metadata areas are exposed,
so you can erase them. Even erasing from Linux is
not foolproof, as sometimes Linux tries to read
the metadata and make it work as it did in Windows.
When I work with a drive, the drive must be
completely clean, as I have had cases where a
later experiment is ruined, because the test
case can "sniff" the metadata from a previous
experiment.

Paul

First off, I never said I wasn't backing up my data. That is not the
issue, as you can see in some of my responses. My sole concern with this
post is the best way to clear up the failed redundancy error. Right now
that sounds like take my new drive and add it to the mirror. Then remove
one of the current mirror drives, test the hell out of it to make sure
there is no hardware problem, then add it back to the mirror. At that
point I should have to good fully redundant drives in the mirror. I can
then remove the other drive that is showing failed redundancy, test the
hell out of it, then use it to replace the other failed drive that is not
part of the scope of this thread.

And totally OT, I understand what you are talking about with data that
hangs around on a disk. Back in the late 90s were were running Microsoft
Lan Manager on a UNIX server (a valid configuration) We had some load
problems and added a second UNIX server for a little while, while we
migrated to Windows NT for the main server. Once that was accomplished, I
got one of the UNIX boxes to use as my desktop, as I had 80286 based PC
at the time. I completely wiped and formatted the drive, and loaded
whatever version of Windows we were using at the time. Every time I
booted the maching, the antivirus software would have a cow about a
bootloader virus. We finally figured out that the UNIX boot block was
larger than the later Windows boot loader, and the antivirus was seeing
the remnants of that block still there behind the valid Windows boot
block. As the song says, "Strange Things Happen In This World".
 




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