How to speed up ddrescue
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0
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I am trying to backup my failing external USB HDD Maxtor M3 4TB using ddrescue.
In the beginning, I was getting around 300kB/s so I ripped the external box and connected the drive directly via SATA to my desktop which improved the rate to around 700kB/s.
After playing with -a (Minimum read rate) -b (block size) -c (Number of sectors to copy at a time) I arrived at
-a 20M -b 4096B -c 2048
Above mentioned combination increased the rate to about 1800kB/s.
Moreover, the current rate fluctuates from a few bytes/s to 115MB/s with the overall average staying around mentioned 1800kB/s.
It feels as if it read at a normal 'healthy drive' rate for a sec and then hang to wait for some timeout and continuing at a reduced rate.
Do you have experience with other parameters that help improve the rate?
Since the whole 4TB drive will take about a month at the current rate any improvement is highly appreciated.
EDIT - Full command
The full command is
sudo ddrescue -a 20M -b 4096 -c 2048 -f -n -vv /dev/sdi /dev/sdh video_drive.log
EDIT 2 - Oh that's why it is so slow
The drive is failing in such a way that S.M.A.R.T. support is disabled at times, but during the periods it works, I noticed the high and increasing value of Read Error Rate and Hardware ECC Recovered fields.
I assume the ECC recovery is the reason why I see no errors and also the reason why the rate is so low.
hard-drive ddrescue
asked Nov 28 at 21:45
badluck
11
add a comment |
up vote
0
down vote
favorite
I am trying to backup my failing external USB HDD Maxtor M3 4TB using ddrescue.
In the beginning, I was getting around 300kB/s so I ripped the external box and connected the drive directly via SATA to my desktop which improved the rate to around 700kB/s.
After playing with -a (Minimum read rate) -b (block size) -c (Number of sectors to copy at a time) I arrived at
-a 20M -b 4096B -c 2048
Above mentioned combination increased the rate to about 1800kB/s.
Moreover, the current rate fluctuates from a few bytes/s to 115MB/s with the overall average staying around mentioned 1800kB/s.
It feels as if it read at a normal 'healthy drive' rate for a sec and then hang to wait for some timeout and continuing at a reduced rate.
Do you have experience with other parameters that help improve the rate?
Since the whole 4TB drive will take about a month at the current rate any improvement is highly appreciated.
EDIT - Full command
The full command is
sudo ddrescue -a 20M -b 4096 -c 2048 -f -n -vv /dev/sdi /dev/sdh video_drive.log
EDIT 2 - Oh that's why it is so slow
The drive is failing in such a way that S.M.A.R.T. support is disabled at times, but during the periods it works, I noticed the high and increasing value of Read Error Rate and Hardware ECC Recovered fields.
I assume the ECC recovery is the reason why I see no errors and also the reason why the rate is so low.
hard-drive ddrescue
asked Nov 28 at 21:45
badluck
11
If the drive is damaged you just have to wait for the retries ...
– DavidPostill♦
Nov 28 at 21:47
I added the full command. As I understand the "-n" skips the retries, so it should not influence it for the first pass right?
– badluck
Nov 28 at 21:53
1
Possible duplicate of Is there any way to speed up ddrescue?
– Kamil Maciorowski
Nov 28 at 22:11
@KamilMaciorowski it is possibly a duplicate, but the difference is that I don't get errors, It's just very slow. That's why I thought maybe there is a way to speed things up.
– badluck
Nov 29 at 10:35
add a comment |
up vote
0
down vote
favorite
up vote
0
down vote
favorite
I am trying to backup my failing external USB HDD Maxtor M3 4TB using ddrescue.
In the beginning, I was getting around 300kB/s so I ripped the external box and connected the drive directly via SATA to my desktop which improved the rate to around 700kB/s.
After playing with -a (Minimum read rate) -b (block size) -c (Number of sectors to copy at a time) I arrived at
-a 20M -b 4096B -c 2048
Above mentioned combination increased the rate to about 1800kB/s.
Moreover, the current rate fluctuates from a few bytes/s to 115MB/s with the overall average staying around mentioned 1800kB/s.
It feels as if it read at a normal 'healthy drive' rate for a sec and then hang to wait for some timeout and continuing at a reduced rate.
Do you have experience with other parameters that help improve the rate?
Since the whole 4TB drive will take about a month at the current rate any improvement is highly appreciated.
EDIT - Full command
The full command is
sudo ddrescue -a 20M -b 4096 -c 2048 -f -n -vv /dev/sdi /dev/sdh video_drive.log
EDIT 2 - Oh that's why it is so slow
The drive is failing in such a way that S.M.A.R.T. support is disabled at times, but during the periods it works, I noticed the high and increasing value of Read Error Rate and Hardware ECC Recovered fields.
I assume the ECC recovery is the reason why I see no errors and also the reason why the rate is so low.
hard-drive ddrescue
asked Nov 28 at 21:45
badluck
11
I am trying to backup my failing external USB HDD Maxtor M3 4TB using ddrescue.
In the beginning, I was getting around 300kB/s so I ripped the external box and connected the drive directly via SATA to my desktop which improved the rate to around 700kB/s.
After playing with -a (Minimum read rate) -b (block size) -c (Number of sectors to copy at a time) I arrived at
-a 20M -b 4096B -c 2048
Above mentioned combination increased the rate to about 1800kB/s.
Moreover, the current rate fluctuates from a few bytes/s to 115MB/s with the overall average staying around mentioned 1800kB/s.
It feels as if it read at a normal 'healthy drive' rate for a sec and then hang to wait for some timeout and continuing at a reduced rate.
Do you have experience with other parameters that help improve the rate?
Since the whole 4TB drive will take about a month at the current rate any improvement is highly appreciated.
EDIT - Full command
The full command is
sudo ddrescue -a 20M -b 4096 -c 2048 -f -n -vv /dev/sdi /dev/sdh video_drive.log
EDIT 2 - Oh that's why it is so slow
The drive is failing in such a way that S.M.A.R.T. support is disabled at times, but during the periods it works, I noticed the high and increasing value of Read Error Rate and Hardware ECC Recovered fields.
I assume the ECC recovery is the reason why I see no errors and also the reason why the rate is so low.
hard-drive ddrescue
hard-drive ddrescue
asked Nov 28 at 21:45
badluck
11
asked Nov 28 at 21:45
badluck
11
edited 2 days ago
asked Nov 28 at 21:45
badluck
11
asked Nov 28 at 21:45
badluck
11
asked Nov 28 at 21:45
badluck
11
11
If the drive is damaged you just have to wait for the retries ...
– DavidPostill♦
Nov 28 at 21:47
I added the full command. As I understand the "-n" skips the retries, so it should not influence it for the first pass right?
– badluck
Nov 28 at 21:53
1
Possible duplicate of Is there any way to speed up ddrescue?
– Kamil Maciorowski
Nov 28 at 22:11
@KamilMaciorowski it is possibly a duplicate, but the difference is that I don't get errors, It's just very slow. That's why I thought maybe there is a way to speed things up.
– badluck
Nov 29 at 10:35
add a comment |
If the drive is damaged you just have to wait for the retries ...
– DavidPostill♦
Nov 28 at 21:47
I added the full command. As I understand the "-n" skips the retries, so it should not influence it for the first pass right?
– badluck
Nov 28 at 21:53
1
Possible duplicate of Is there any way to speed up ddrescue?
– Kamil Maciorowski
Nov 28 at 22:11
@KamilMaciorowski it is possibly a duplicate, but the difference is that I don't get errors, It's just very slow. That's why I thought maybe there is a way to speed things up.
– badluck
Nov 29 at 10:35
If the drive is damaged you just have to wait for the retries ...
– DavidPostill♦
Nov 28 at 21:47
If the drive is damaged you just have to wait for the retries ...
– DavidPostill♦
Nov 28 at 21:47
I added the full command. As I understand the "-n" skips the retries, so it should not influence it for the first pass right?
– badluck
Nov 28 at 21:53
I added the full command. As I understand the "-n" skips the retries, so it should not influence it for the first pass right?
– badluck
Nov 28 at 21:53
1
1
Possible duplicate of Is there any way to speed up ddrescue?
– Kamil Maciorowski
Nov 28 at 22:11
Possible duplicate of Is there any way to speed up ddrescue?
– Kamil Maciorowski
Nov 28 at 22:11
@KamilMaciorowski it is possibly a duplicate, but the difference is that I don't get errors, It's just very slow. That's why I thought maybe there is a way to speed things up.
– badluck
Nov 29 at 10:35
@KamilMaciorowski it is possibly a duplicate, but the difference is that I don't get errors, It's just very slow. That's why I thought maybe there is a way to speed things up.
– badluck
Nov 29 at 10:35
add a comment |
1 Answer
1
active
oldest
votes
up vote
1
down vote
When ddrescue reads the disk, it has to read every block. It cannot know in advance which blocks are bad. So it will inevitably try to read a bad block. The disk will try very hard to correctly read this block before giving up and returning an error. This behavior cannot be disabled or controlled on consumer-grade hard drives.
So even without ddrescue retrying, bad blocks will slow down the process a lot. There is nothing you can do except keep going.
answered Nov 28 at 22:07
Daniel B
33k75986
When it reads the bad block it increases theerrors, right? But since theerrorsparameter does not increase I assume it's not encountering any error.
– badluck
Nov 29 at 10:31
The hard drive could always succeed at making those blocks readable, too! Which would be even better for you, because you'd get the data.
– Daniel B
Nov 29 at 12:53
add a comment |
1 Answer
1
active
oldest
votes
1 Answer
1
active
oldest
votes
active
oldest
votes
active
oldest
votes
up vote
1
down vote
When ddrescue reads the disk, it has to read every block. It cannot know in advance which blocks are bad. So it will inevitably try to read a bad block. The disk will try very hard to correctly read this block before giving up and returning an error. This behavior cannot be disabled or controlled on consumer-grade hard drives.
So even without ddrescue retrying, bad blocks will slow down the process a lot. There is nothing you can do except keep going.
answered Nov 28 at 22:07
Daniel B
33k75986
When it reads the bad block it increases theerrors, right? But since theerrorsparameter does not increase I assume it's not encountering any error.
– badluck
Nov 29 at 10:31
The hard drive could always succeed at making those blocks readable, too! Which would be even better for you, because you'd get the data.
– Daniel B
Nov 29 at 12:53
add a comment |
up vote
1
down vote
When ddrescue reads the disk, it has to read every block. It cannot know in advance which blocks are bad. So it will inevitably try to read a bad block. The disk will try very hard to correctly read this block before giving up and returning an error. This behavior cannot be disabled or controlled on consumer-grade hard drives.
So even without ddrescue retrying, bad blocks will slow down the process a lot. There is nothing you can do except keep going.
answered Nov 28 at 22:07
Daniel B
33k75986
When it reads the bad block it increases theerrors, right? But since theerrorsparameter does not increase I assume it's not encountering any error.
– badluck
Nov 29 at 10:31
The hard drive could always succeed at making those blocks readable, too! Which would be even better for you, because you'd get the data.
– Daniel B
Nov 29 at 12:53
add a comment |
up vote
1
down vote
up vote
1
down vote
When ddrescue reads the disk, it has to read every block. It cannot know in advance which blocks are bad. So it will inevitably try to read a bad block. The disk will try very hard to correctly read this block before giving up and returning an error. This behavior cannot be disabled or controlled on consumer-grade hard drives.
So even without ddrescue retrying, bad blocks will slow down the process a lot. There is nothing you can do except keep going.
answered Nov 28 at 22:07
Daniel B
33k75986
When ddrescue reads the disk, it has to read every block. It cannot know in advance which blocks are bad. So it will inevitably try to read a bad block. The disk will try very hard to correctly read this block before giving up and returning an error. This behavior cannot be disabled or controlled on consumer-grade hard drives.
So even without ddrescue retrying, bad blocks will slow down the process a lot. There is nothing you can do except keep going.
answered Nov 28 at 22:07
Daniel B
33k75986
answered Nov 28 at 22:07
Daniel B
33k75986
answered Nov 28 at 22:07
Daniel B
33k75986
answered Nov 28 at 22:07
Daniel B
33k75986
33k75986
When it reads the bad block it increases theerrors, right? But since theerrorsparameter does not increase I assume it's not encountering any error.
– badluck
Nov 29 at 10:31
The hard drive could always succeed at making those blocks readable, too! Which would be even better for you, because you'd get the data.
– Daniel B
Nov 29 at 12:53
add a comment |
When it reads the bad block it increases theerrors, right? But since theerrorsparameter does not increase I assume it's not encountering any error.
– badluck
Nov 29 at 10:31
The hard drive could always succeed at making those blocks readable, too! Which would be even better for you, because you'd get the data.
– Daniel B
Nov 29 at 12:53
When it reads the bad block it increases the
errors, right? But since the errors parameter does not increase I assume it's not encountering any error.– badluck
Nov 29 at 10:31
When it reads the bad block it increases the
errors, right? But since the errors parameter does not increase I assume it's not encountering any error.– badluck
Nov 29 at 10:31
The hard drive could always succeed at making those blocks readable, too! Which would be even better for you, because you'd get the data.
– Daniel B
Nov 29 at 12:53
The hard drive could always succeed at making those blocks readable, too! Which would be even better for you, because you'd get the data.
– Daniel B
Nov 29 at 12:53
add a comment |
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If the drive is damaged you just have to wait for the retries ...
– DavidPostill♦
Nov 28 at 21:47
I added the full command. As I understand the "-n" skips the retries, so it should not influence it for the first pass right?
– badluck
Nov 28 at 21:53
1
Possible duplicate of Is there any way to speed up ddrescue?
– Kamil Maciorowski
Nov 28 at 22:11
@KamilMaciorowski it is possibly a duplicate, but the difference is that I don't get errors, It's just very slow. That's why I thought maybe there is a way to speed things up.
– badluck
Nov 29 at 10:35