RAID-1 and bad sectors?
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From: void on 30 Dec 2005 05:29 I just used BootItNG to resize the 2 NTFS partitions on my hard disk. I was increasing the size of the C drive, so I had to shrink the D drive and slide it down to the end of the disk. When I did the slide operation, I told it to slide everything including the unused areas. I ended up getting an "error reading from hard disk" message. So I retried the slide operation, but just told it to slide the data only. That worked, so maybe there was a bad sector in an unused area? Anyways, I'm now ready to set up RAID-1 in my system. But I'm wondering if that bad sector might cause a problem in a RAID-1 setup? I know RAID-1 is supposed help you if a drive fails. But what if a drive doesn't totally stop working... what if it only develops a few bad sectors? Can RAID-1 handle that? (I'll be using the HighPoint 370 controller on my Abit KT7-RAID motherboard.) Like what would happen if the RAID controller is writing some data, and one of the drives is OK but the other drive has some bad sectors on it? Can the RAID controller detect the bad sectors and write the data to good sectors? Or will it not detect the bad sectors and the 2 drives will be out-of-sync?
From: philo on 30 Dec 2005 06:41 <void(a)no.spam.com> wrote in message news:46v9r195r6m540q3b8ef5ikn08kdjn6380(a)4ax.com... > I just used BootItNG to resize the 2 NTFS partitions on my hard disk. I was > increasing the size of the C drive, so I had to shrink the D drive and slide > it down to the end of the disk. When I did the slide operation, I told it to > slide everything including the unused areas. I ended up getting an "error > reading from hard disk" message. So I retried the slide operation, but just > told it to slide the data only. That worked, so maybe there was a bad sector > in an unused area? Go to the website of the HD's mfg and download the diagnostic utility and run it. If *any* errors are found..backup your data and replace the disc. At any rate...I'd never use a drive with bad sectors in a RAID situation
From: Chuck F. on 30 Dec 2005 06:47 void(a)no.spam.com wrote: > > I just used BootItNG to resize the 2 NTFS partitions on my hard > disk. I was increasing the size of the C drive, so I had to > shrink the D drive and slide it down to the end of the disk. > When I did the slide operation, I told it to slide everything > including the unused areas. I ended up getting an "error > reading from hard disk" message. So I retried the slide > operation, but just told it to slide the data only. That > worked, so maybe there was a bad sector in an unused area? Which may mean that you wrote some of your actual data into a failing "unused" area, and that that data is now lost or altered. I wouldn't trust anything that was on that partition. -- "If you want to post a followup via groups.google.com, don't use the broken "Reply" link at the bottom of the article. Click on "show options" at the top of the article, then click on the "Reply" at the bottom of the article headers." - Keith Thompson More details at: <http://cfaj.freeshell.org/google/>
From: Arno Wagner on 30 Dec 2005 11:29 In comp.sys.ibm.pc.hardware.storage void(a)no.spam.com wrote: > I just used BootItNG to resize the 2 NTFS partitions on my hard > disk. I was increasing the size of the C drive, so I had to shrink > the D drive and slide it down to the end of the disk. When I did > the slide operation, I told it to slide everything including the > unused areas. I ended up getting an "error reading from hard disk" > message. So I retried the slide operation, but just told it to > slide the data only. That worked, so maybe there was a bad sector > in an unused area? > Anyways, I'm now ready to set up RAID-1 in my system. But I'm > wondering if that bad sector might cause a problem in a RAID-1 > setup? I know RAID-1 is supposed help you if a drive fails. But > what if a drive doesn't totally stop working... what if it only > develops a few bad sectors? Can RAID-1 handle that? (I'll be using > the HighPoint 370 controller on my Abit KT7-RAID motherboard.) Like > what would happen if the RAID controller is writing some data, and > one of the drives is OK but the other drive has some bad sectors on > it? Can the RAID controller detect the bad sectors and write the > data to good sectors? Or will it not detect the bad sectors and the > 2 drives will be out-of-sync? It will detect a bad sector only if it reads from it. In that case it will fail-over to the other disk. Many RAID controllers will also mark the disk as bad and kick it form the array. If you have bad sectors on eiter disk in different places that behaviour is not too desirable, but in this case you are in trouble anyways, since modern disks only exhibit bad sectors if they are dying or have very serious problems. Now, you might be in this situation and then your best bet is possibly RAID recovery software (have seen some, don't remember where) or if your controller allows you to disable the kicking on defects. Linux software RAID seems not to allow you to do that. What I would do in such a case is to mount both partitions/drives read-only, determine which has less bad sectors, write them down and copy that partition/drive to a good one. Then copy the bad sectors on the first drive from the second one. If ithe number of bad sectros is high, then script this using, e.g., badblocks and dd_rescue. When writing to a bad sector, the data will be written to both drives. Since the data is written with checksums, the the controller will recognize a bad sector and read it form the other disk. See also above. Arno
From: Rod Speed on 30 Dec 2005 13:27
void(a)no.spam.com wrote: > I just used BootItNG to resize the 2 NTFS partitions on my hard disk. > I was increasing the size of the C drive, so I had to shrink the D > drive and slide it down to the end of the disk. When I did the slide > operation, I told it to slide everything including the unused areas. > I ended up getting an "error reading from hard disk" message. So I > retried the slide operation, but just told it to slide the data only. > That worked, so maybe there was a bad sector in an unused area? Its important to check that possibility before doing anything else. Use Everest to check the SMART data for the drive, post it here. http://www.majorgeeks.com/download.php?det=4181 Also run the hard drive manufacturer's diagnostic on that drive. It might just have been a quirk of BootItNG, it can be pretty buggy. > Anyways, I'm now ready to set up RAID-1 in my system. But I'm > wondering if that bad sector might cause a problem in a RAID-1 setup? > I know RAID-1 is supposed help you if a drive fails. But what if a > drive doesn't totally stop working... what if it only develops a few > bad sectors? Can RAID-1 handle that? (I'll be using the HighPoint > 370 controller on my Abit KT7-RAID motherboard.) Like what would > happen if the RAID controller is writing some data, and one of the > drives is OK but the other drive has some bad sectors on it? Can the > RAID controller detect the bad sectors and write the data to good > sectors? Or will it not detect the bad sectors and the 2 drives will > be out-of-sync? Dont worry about any of this until you prove that the drive does have bad sectors. |