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Remove GRUB and rebuild MBR - how?
clarification on use of FDSK needed.
HarryM




msg:912345
 8:44 pm on Mar 2, 2003 (gmt 0)

I have a multiboot system with Win98 and 3 versions Win2000 to which I have added Red Hat Linux 8 putting GRUB on the MBR - big mistake. :(

All Windows systems work OK but all Win2000s have problems displaying Logical Disk Volumes in Windows Explorer, or My Computer, or in Disk Management. They get there eventually but take minutes not msecs. Start up and shut down times have inalso increased. Presumably this due to GRUB overwriting the Partition Table.

I understand that fdsk/mrb will remove GRUB, but am unsure if this rebuilds the complete Partition Table, and what it does about the Linux partitions.

Can anyone explain - or suggest another solution?

 

sequencher




msg:912346
 6:42 am on Mar 3, 2003 (gmt 0)

Sorry to hear your multiboot hasn't gone well. In a small number of multiboots this happens and seem to be a local setup problem, other times it goes smoothly. Not sure why.

What is likely happening is that Win2k will search the logical drives looking for other NTFS/FAT partitions. When it hits the Linux ext3 partition it chokes and scans the partition (which is why it takes forever to load or do any kind of disk indexing operation). I've seen several work arounds for this and they all try to "hide" the linux partitions from Win2k. You can google for these, however they have varying results.

I'm not sure if running "fdisk /MBR" is the way to go. I think it may only work for 95/98/Me. I usually boot from the Win2k install CD and go into the recovery mode. From there you can run fixmbr. However, if you do reinstall the win2k bootloader, you won't be able to boot the linux partitions.

If you you are still serious about running linux AND the win2k bootloader you can try this, but at your own risk: [enterprisedt.com...]

Maybe looking into "Running linux from a CD" is a good idea.

HarryM




msg:912347
 6:44 pm on Mar 3, 2003 (gmt 0)

Sequencher, thanks for the help.

I have now run Fixmbr from the recovery console and it overwrote GRUB. Also ran Map which showed all partitions had been found, but the Linux partitions were not given letters which looked OK to me.

However my main Win2000 system boots just as slowly, and when I double-click My Computer it searches for at least a minute before finally displaying the partitions. As before it only shows 1 Linux partition, and has given it a letter. So its presumably not getting its info from MBR.

Any suggestions? I'ma about to start tearing my hair. :(

sequencher




msg:912348
 1:35 am on Mar 4, 2003 (gmt 0)

This is a shot in the dark, but check and see if you have disk indexing turned on. To do this: open the control panel, Administrative Tools, Computer Management. Double click on the Services and Applications icon in the directory tree (left handed window) so that the subdirectories are shown. There should be a couple options here (on mine: WMI Control, Services, and Indexing Services). Click once on Indexing to highlight it. Now click on the Actions button at the top. If you have the option to stop the service, that means it's on (which might be the problem). Try stopping the indexing service and see if that improves performance.

I don't think it will be that easy though. You may have to tell it not to try and index the linux partition and then rebuild the catalog. Let me know if you have the Indexing service even on first before you try that.

If you're ready to cut your losses at this point you may just want to reformat the linux partitions with NTFS or FAT. I can't say I would blame you. Trying to get a dual boot system working can be a real pain when things don't go smoothly. 9 out of 10 times it's simple, but when you have problems it can get ugly real fast. Trust me I know how that feels.

HarryM




msg:912349
 2:38 am on Mar 4, 2003 (gmt 0)

Indexing Services are off, but I think I have now got the problem sorted.

I checked the disk with FDISK from a Win98 floppy, and the Linux partitions were not displayed. These had been created by Red Hat's Disk Druid.

Created 3 new partitions with FDISK in the same area which would have overwritten the Linux partitions. Then formatted and set mount points with Disk Druid and reinstalled Red Hat. GRUB is now on the /boot partition and I can boot Linux from a floppy.

Bingo! Linux is running and Win2000 back to normal. :)

It looks as if GRUB on MBR may not have been the problem, but I'm not going to chance putting it back. Will create a link from NTLDR to GRUB as per the url you supplied. In fact I have found other sites that advise this method, so it should be OK.

Thanks for your help.

sequencher




msg:912350
 3:29 am on Mar 4, 2003 (gmt 0)

No problem, glad you got your multiboot to work.

Strange that was the cause of the problem. I wonder if it's due to the way DiskDruid creates partitions or if the problem is with having Grub somewhere besides /boot? One of the work arounds I've seen involved using PartitionMagic to create the linux partitions instead of DiskDruid, so maybe there is some validity to that. Curious indeed.

HarryM




msg:912351
 12:20 pm on Mar 4, 2003 (gmt 0)

I suspect it's due to the way Disk Druid creates partitions.

Partitions created by DiskDruid

- No partitions recognized by FDISK
- all 3 partitions (eventually) recognized by Logical Disk Manager, but only /root given a letter
- Only /root partition (eventually) showed in Windows Explorer or My Computer. It had the same letter.

Partitions created by FDISK

- all 3 partitions recognized by FDISK
- all 3 partitions immediately recognized by Logical Disk Manager and all 3 given letters in correct sequence.
- all 3 partitions immediately showed in Windows Explorer and My Computer and all given letters. However sequence different. /root was in the correct sequence, but /swap and /boot were given letters following those of other partitions on a second hard disk. But this doesn't seem to be a cause for concern.

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