If a RAID5 system experiences a URE during rebuild, is all the data lost?
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I understand the argument regarding larger drives' increased likelihood of experiencing a URE during a rebuild, however I'm not sure what the actual implications are for this. This answer says that the entire rebuild fails, but does this mean that all the data is inaccessible? Why would that be? Surely a single URE from a single sector on the drive would only impact the data related to a few files, at most. Wouldn't the array still be rebuilt, just with some minor corruption to a few files?
(I'm specifically interested in ZFS's implementation of RAID5 here, but the logic seems the same for any RAID5 implementation.)
raid zfs zfsonlinux
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up vote
1
down vote
favorite
I understand the argument regarding larger drives' increased likelihood of experiencing a URE during a rebuild, however I'm not sure what the actual implications are for this. This answer says that the entire rebuild fails, but does this mean that all the data is inaccessible? Why would that be? Surely a single URE from a single sector on the drive would only impact the data related to a few files, at most. Wouldn't the array still be rebuilt, just with some minor corruption to a few files?
(I'm specifically interested in ZFS's implementation of RAID5 here, but the logic seems the same for any RAID5 implementation.)
raid zfs zfsonlinux
add a comment |Â
up vote
1
down vote
favorite
up vote
1
down vote
favorite
I understand the argument regarding larger drives' increased likelihood of experiencing a URE during a rebuild, however I'm not sure what the actual implications are for this. This answer says that the entire rebuild fails, but does this mean that all the data is inaccessible? Why would that be? Surely a single URE from a single sector on the drive would only impact the data related to a few files, at most. Wouldn't the array still be rebuilt, just with some minor corruption to a few files?
(I'm specifically interested in ZFS's implementation of RAID5 here, but the logic seems the same for any RAID5 implementation.)
raid zfs zfsonlinux
I understand the argument regarding larger drives' increased likelihood of experiencing a URE during a rebuild, however I'm not sure what the actual implications are for this. This answer says that the entire rebuild fails, but does this mean that all the data is inaccessible? Why would that be? Surely a single URE from a single sector on the drive would only impact the data related to a few files, at most. Wouldn't the array still be rebuilt, just with some minor corruption to a few files?
(I'm specifically interested in ZFS's implementation of RAID5 here, but the logic seems the same for any RAID5 implementation.)
raid zfs zfsonlinux
raid zfs zfsonlinux
asked 1 hour ago
process91
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1113
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2 Answers
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I would explain it the other way around;
If the RAID controller donâÂÂt stop on URE, what could happen ?
I lived it on a server, the RAID never noticed the URE and after the rebuild a corruption started to build up on the entire RAID volume.
The disk started to get more bad sector after the rebuild and the data started to be corrupt.
The disk was never kicked off the RAID volume, the controller fail is job to protect the data integrity.
That example is wrote to make you think that a controller canâÂÂt thrust a volume with URE at all, its for the data integrity, as the volume is not meant to be a backup but a resiliance to a disk failure
1
I see the new moderators are all constantly checking the site, looking for things to do...
â Wardâ¦
43 mins ago
@Ward haha, yeah :)
â yagmoth555â¦
39 mins ago
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I'd suggest reading this question and answers for a bit more background. Then go and re-read the question you linked to again.
When someone says about this situation that "the RAID failed," it means you lost the benefit of the RAID - you lost the continuous access to data that was the reason you set up the RAID array in the first place.
You haven't lost all the data, but the most common way to recover from one dead drive plus (some) UREs on (some of) the remaining drives would be to completely rebuild the array from scratch, which will mean restoring all your data from backup.
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2 Answers
2
active
oldest
votes
2 Answers
2
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
I would explain it the other way around;
If the RAID controller donâÂÂt stop on URE, what could happen ?
I lived it on a server, the RAID never noticed the URE and after the rebuild a corruption started to build up on the entire RAID volume.
The disk started to get more bad sector after the rebuild and the data started to be corrupt.
The disk was never kicked off the RAID volume, the controller fail is job to protect the data integrity.
That example is wrote to make you think that a controller canâÂÂt thrust a volume with URE at all, its for the data integrity, as the volume is not meant to be a backup but a resiliance to a disk failure
1
I see the new moderators are all constantly checking the site, looking for things to do...
â Wardâ¦
43 mins ago
@Ward haha, yeah :)
â yagmoth555â¦
39 mins ago
add a comment |Â
up vote
1
down vote
I would explain it the other way around;
If the RAID controller donâÂÂt stop on URE, what could happen ?
I lived it on a server, the RAID never noticed the URE and after the rebuild a corruption started to build up on the entire RAID volume.
The disk started to get more bad sector after the rebuild and the data started to be corrupt.
The disk was never kicked off the RAID volume, the controller fail is job to protect the data integrity.
That example is wrote to make you think that a controller canâÂÂt thrust a volume with URE at all, its for the data integrity, as the volume is not meant to be a backup but a resiliance to a disk failure
1
I see the new moderators are all constantly checking the site, looking for things to do...
â Wardâ¦
43 mins ago
@Ward haha, yeah :)
â yagmoth555â¦
39 mins ago
add a comment |Â
up vote
1
down vote
up vote
1
down vote
I would explain it the other way around;
If the RAID controller donâÂÂt stop on URE, what could happen ?
I lived it on a server, the RAID never noticed the URE and after the rebuild a corruption started to build up on the entire RAID volume.
The disk started to get more bad sector after the rebuild and the data started to be corrupt.
The disk was never kicked off the RAID volume, the controller fail is job to protect the data integrity.
That example is wrote to make you think that a controller canâÂÂt thrust a volume with URE at all, its for the data integrity, as the volume is not meant to be a backup but a resiliance to a disk failure
I would explain it the other way around;
If the RAID controller donâÂÂt stop on URE, what could happen ?
I lived it on a server, the RAID never noticed the URE and after the rebuild a corruption started to build up on the entire RAID volume.
The disk started to get more bad sector after the rebuild and the data started to be corrupt.
The disk was never kicked off the RAID volume, the controller fail is job to protect the data integrity.
That example is wrote to make you think that a controller canâÂÂt thrust a volume with URE at all, its for the data integrity, as the volume is not meant to be a backup but a resiliance to a disk failure
answered 53 mins ago
yagmoth555â¦
10.8k31441
10.8k31441
1
I see the new moderators are all constantly checking the site, looking for things to do...
â Wardâ¦
43 mins ago
@Ward haha, yeah :)
â yagmoth555â¦
39 mins ago
add a comment |Â
1
I see the new moderators are all constantly checking the site, looking for things to do...
â Wardâ¦
43 mins ago
@Ward haha, yeah :)
â yagmoth555â¦
39 mins ago
1
1
I see the new moderators are all constantly checking the site, looking for things to do...
â Wardâ¦
43 mins ago
I see the new moderators are all constantly checking the site, looking for things to do...
â Wardâ¦
43 mins ago
@Ward haha, yeah :)
â yagmoth555â¦
39 mins ago
@Ward haha, yeah :)
â yagmoth555â¦
39 mins ago
add a comment |Â
up vote
1
down vote
I'd suggest reading this question and answers for a bit more background. Then go and re-read the question you linked to again.
When someone says about this situation that "the RAID failed," it means you lost the benefit of the RAID - you lost the continuous access to data that was the reason you set up the RAID array in the first place.
You haven't lost all the data, but the most common way to recover from one dead drive plus (some) UREs on (some of) the remaining drives would be to completely rebuild the array from scratch, which will mean restoring all your data from backup.
add a comment |Â
up vote
1
down vote
I'd suggest reading this question and answers for a bit more background. Then go and re-read the question you linked to again.
When someone says about this situation that "the RAID failed," it means you lost the benefit of the RAID - you lost the continuous access to data that was the reason you set up the RAID array in the first place.
You haven't lost all the data, but the most common way to recover from one dead drive plus (some) UREs on (some of) the remaining drives would be to completely rebuild the array from scratch, which will mean restoring all your data from backup.
add a comment |Â
up vote
1
down vote
up vote
1
down vote
I'd suggest reading this question and answers for a bit more background. Then go and re-read the question you linked to again.
When someone says about this situation that "the RAID failed," it means you lost the benefit of the RAID - you lost the continuous access to data that was the reason you set up the RAID array in the first place.
You haven't lost all the data, but the most common way to recover from one dead drive plus (some) UREs on (some of) the remaining drives would be to completely rebuild the array from scratch, which will mean restoring all your data from backup.
I'd suggest reading this question and answers for a bit more background. Then go and re-read the question you linked to again.
When someone says about this situation that "the RAID failed," it means you lost the benefit of the RAID - you lost the continuous access to data that was the reason you set up the RAID array in the first place.
You haven't lost all the data, but the most common way to recover from one dead drive plus (some) UREs on (some of) the remaining drives would be to completely rebuild the array from scratch, which will mean restoring all your data from backup.
answered 43 mins ago
Wardâ¦
11.4k53855
11.4k53855
add a comment |Â
add a comment |Â
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