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I have a drive with this configuration:

fdisk -l

Disk /dev/sda: 500.1 GB, 500107862016 bytes
255 heads, 63 sectors/track, 60801 cylinders
Units = cylinders of 16065 * 512 = 8225280 bytes
Sector size (logical/physical): 512 bytes / 4096 bytes
I/O size (minimum/optimal): 4096 bytes / 4096 bytes
Disk identifier: 0x000f1b8b

   Device Boot      Start         End      Blocks   Id  System
/dev/sda1   *           1        2612    20971520   83  Linux
/dev/sda3           60736       60801      525312   82  Linux swap / Solaris

There is 478GB unallocated space, how would I go about adding this space to /dev/sda1 without losing the data that is currently on /dev/sda1? (the filesystem is ext4) The OS is debian 6. Thank you in advance. :)
(it is a server with only SSH, no GUI for running stuff like gparted)

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I can netboot the server and use it while the drive is unmounted. –  Seb Mar 6 '13 at 20:08
Sorry 'bout the criss cross, lol -- I put that stuff into an answer. –  goldilocks Mar 6 '13 at 20:15
This particular item has been covered many many times within the SE sites. It would be best to do just a little bit more research before posting a question. –  mdpc Mar 7 '13 at 2:17

3 Answers 3

up vote 8 down vote accepted

Enlarge the partition: fdisk -u /dev/sda.

p to print the partition table, take note of the number, start, end, type of sda1.

Delete it: d:

Recreate it with same number (1), start and type but with a bigger end (taking care not to overlap with other partitions). Try to align things on a megabyte boundary that is for end, make it a multiple of 2048 minus 1. Change the type if needed with t (for partitions holding an extX or btrfs filesystem, the default of 83 is fine).

Then w to write and q to quit.

The partition table will have been modified but the kernel will not be able to take that into account as some partitions are mounted.

However, if in-use partitions were only enlarged, you should be able to force the kernel to take the new layout with:

partx /dev/sda

If that fails, you'll need to reboot. The system should boot just fine.

Then, resize the filesystem so it spreads to the extent of the enlarged partition:

resize2fs /dev/sda1

Which for ext4 will work just fine even on a live FS.

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Worked great :) thanks. –  Seb Mar 6 '13 at 21:11
I know this is old, but will this keep the data if you delete the partition? –  Canadian Luke May 7 '14 at 3:02
@CanadianLuke, yes, deleting the partition in fdisk only modifies the partition table. If you recreate it the same size, there will be no change at all. The data is never altered unless you shrink a partition and create another logical or extended partition in the middle of what your partition used to be, in which case the partition record for that extended/logical partition will be written over some data there. –  Stéphane Chazelas May 7 '14 at 10:47
This also works great for ntfs partitions (with an existing volume, with data). –  Kenny Evitt Aug 2 '14 at 19:55

You can't do it safely while the partition is mounted, meaning you need to boot some other partition and do it from there.

gparted is a nice, easy GUI for this purpose. In our deleted comment exchange you mentioned it would not start because of "can't access display" -- this implies you aren't in X; since it is a GUI it won't work without that.

Of course, if you don't have another partition to use, you'll need a live CD or something -- I think they usually come with gparted. Your best bet is probably the actual gparted live CD, which looks to have a reasonably recent latest stable version (and will fit on a CD, which is nice since the "live CD" is rapidly becoming the "live DVD").

I've never had gparted cause a problem but of course do back your important tish up first.

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I can't use gparted as I only have SSH access (it is a headless server). I am able to unmount the HDD, as the system does not run on /dev/sda. –  Seb Mar 6 '13 at 20:17
If you don't have physical access to the system and thus can't usefully unmount and change the partition, I think you are out of luck, or at least into very sketchy territory -- eg, you could attempt to use fdisk while mounted, select (x)pert, (c)hange number of cylinders. But I have not done this and would only do so if there was absolutely no other choice. –  goldilocks Mar 6 '13 at 20:25
I just said that I can unmount the partition. I can even netboot the whole server and go in from another server, which would be just like using a Live CD (just without a GUI). –  Seb Mar 6 '13 at 20:28
@Seb : my bad, sorry. –  goldilocks Mar 6 '13 at 21:32

I know this is very old issue, but many people are looking for that resolve.

For this example you have typical situation. On the beginning is single partition, and on the end swap partition is located. it isn't good because swap can be havely loaded, and end of rotated disk is the slowest part of it. what I suggest? 1. Create boot partition at the begin. Why at the begin? because many tools have got problems with end of large disk above 2TB barier. After boot partition should be swap partition. This is for performance. Rest of disk should be used for other partitions.

But what with this situation? I don't recommend expanding sda1. I suggest creating other partitions after sda1 & sda2, mounted as /home and /usr . on that directories are stored the most user and system data, and it is possible to securely move data from that directories to new partitions.

But. (second "but") if you still want keep your current structure, you shuld: first remove swap partition. you should do swapoff, remark this in /etc fstab. if swapon tells you (see man) no swap is used, you can remove it by partition tool (fdisk or similar). when you don't have got this partition, you can enlarge your sda1. using fdisk you should firstly print partition. it is for remembering where it starts. secondly remove partition using 'd' key. don't panic, nothing is written to hard drive :) after print you see, no partition exist on the disk. next create new partition. be careful. see on what sector original partition started. write the same number. after that look at the end. fdisk prompt you for last available sector. use calculator and assign in your mind how much swap do you need in kilobytes. multiple it by 2, and substract this number from last sector number prompted by fdisk. create partition. print this (it is still in fdisk temporary memory), and look all is ok. after this press 'w' key, this will tru write new partitioning to the drive. you will see information all is synced, or sync is failed. if failed, you can call command partx /dev/sda for doing sync. if it still fails, you should reboot your system. after reboot you have prepared larger partition, but filesystem on it is still smaller. you should grow it. ext4 is growable on the fly :) use resize2fs /dev/sda1 for do it. you don't need remounting rebooting etc. last, you should restore swap partition. simply use fdisk again, create new partition as swap. after writing 'w', device sda2 will be restored. prepare swap structure on it using mkswap /dev/sda2 , remove remarks for swap on /etc/fstab and finally do swapon -a . look using swapon or top command, swap is activated.

i know, it's very long explanation. I hope it will be usable for any. notice, in my opinion xfs filesystem is much better, unfortunately this fs doesn't support shrinking without temporary copying to alternate place. but shrink is used rarely. it is nice, xfs takes extremaly little place for his own metadata, and is faster in many ways in comparation to ext4.

another hinit, better use some LVM as middle layer for partitioning. after that any resizing is much easier. performance is comparable. of course, you can use mix of hdd managament. you can use in common raw partitions and lvm.

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