Tagged Questions

Questions about disk drives under the UNIX and Linux systems. See also the "filesystems" tag.

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3
votes
2answers
2k views

How to Add Extra Disks on KVM based VM

I installed Redhat 6.4 on KVM Server. Right Now there is only One Disk /dev/vda. Now I need to add extra Disk like /dev/vdb I tried adding New Volume but it is not showing when I do fdisk -l How to ...
1
vote
0answers
164 views

How different is I/O handling of hard disk in AIX and Redhat Linux?

I am running a hadoop I/O workload in redhat linux and have ran that in IBM AIX as well with same underlying hardware, disk and disk configuration. With the default settings on the os redhat linux is ...
3
votes
4answers
392 views

How can I zero files out inside a VMware image file so that their space can be reclaimed?

is there a command on Linux to remove a file but zeroing it's contents first? so if i do, something like this: rm -rf /var/cache/pacman/pkg/* it would overwrite each file on that directory with 0 ...
1
vote
1answer
779 views

How to measure total disk I/O per hour

I have a cloud server were we get billed also for disk IO usage. Here is an example from the stats: 04/Sep/2013 07:24:19 04/Sep/2013 08:24:19 0,5 GB / 1 vCPU (0,08 Kr. per hour): Charge for ...
13
votes
2answers
886 views

How to detect if a disk is seeking?

I can use a variety of tools to measure the volume of disk I/O currently flowing through the system (such as iotop and iostat) but I'm curious if it's possible to easily detect if a disk is seeking a ...
6
votes
4answers
331 views

Are short-lived files flushed to disk?

My program creates many small short-lived files. They are typically deleted within a second after creation. The files are in an ext4 file system backed by a real hard disk. I know that Linux ...
1
vote
1answer
84 views

Strange problem with IO or file system or what?

On a SLES 11 SP2 32-bit system I'm seeing a strange problem. It's as if the OS can not open a file from the beginning of the file. Say I have a file that is 200 lines. If I cat or more or vi the ...
10
votes
3answers
2k views

How to get total number of bytes/sectors/blocks written to disk since booting?

I'm considering and update from HDD to SSD. But since Flash cells can only sustain limited writes. I want to know how much data my computer write during normal operation. So I can determine how long ...
1
vote
2answers
278 views

Setting up a RAID 1 in Funtoo [closed]

In short Following the guide How to Set Up a RAID 1 Under GNU/Linux, I have setup a RAID 1. Checking the RAID Array for validity in various ways, appeared to be normal. However, after rebooting the ...
1
vote
2answers
71 views

Create my own disk server

I have been wondering how all these small nas boxes that run linux can share over network and usb. The network part is totally under control, but I am completely at a loss on how I could hook up a ...
0
votes
1answer
60 views

Why I got a strange result for fdisk -l

root@host [~]# fdisk -l Disk /dev/sdc: 128.0 GB, 128035676160 bytes 255 heads, 63 sectors/track, 15566 cylinders Units = cylinders of 16065 * 512 = 8225280 bytes Sector size (logical/physical): 512 ...
0
votes
3answers
503 views

Deleted files from home, deleted them from .local/share/Trash/files, System doesn't report back free space

I am running Crunchbang, a Debian variant with OpenBox WM. I have deleted a large number of files via browsing in thunar file manager and pressing del key. They disappear from view. I then go to ...
1
vote
1answer
397 views

Changing drives in FTP

I am using RHEL6 and I connect to FileZilla FTP Server in Windows 2008 Server which has more than 10 drives. I have access to all of them but for my user C:\ is Home Directory. I want to change to ...
5
votes
2answers
444 views

How do I refresh the magnetic state on a disks with backups?

I have a couple of large disks with backup/archive material on them. They're ext4. Regarding the ones of those that will be stored for a couple of years without reading the whole disc again I've been ...
0
votes
1answer
49 views

Redundant array of NTFS disks

I have a number of NTFS disks with unused capacity. They are leftover external hard drives with a Windows history. I have a very limited number of USB ports on my machine, and want to find a cheap way ...
1
vote
1answer
374 views

How to realign a disk on logical volume with minimum to zero down time

A system running un-align disk partition that needs to be aligned without loss of data on all the partition including mbr with the minimum to no down time.
3
votes
1answer
2k views

What's the easiest way to decrypt a disk partition?

I made a mistake of encrypting the entire LVM physical volume (contains both home, root, and swap) when installing a CentOS 6.4 (2.6.32-358.6.1.el6.x86_64) box. I soon came to realize that moving ...
0
votes
1answer
148 views

Disk Partitioning - Can't create partition

I've been following this example to restore capacity to my microSD --> SD card corrupt and stuck at 32MB, any way to fix it? Everything seems to work until I get to mkfs /dev/sdx1 It tells me ...
2
votes
3answers
226 views

Any programs suitable for making a database over disk-content?

I have quite a lot of external hard-drives, and often have a hard time finding what I'm looking for - not to mention not storing the same file several times on different drives or finding free space ...
2
votes
2answers
1k views

How to use DD to clone a partition off a disk image?

I have a disk image, it's a "whole" disk image, e.g., contains multiple partitions, and I want to clone just one of them (not the first one..) onto a partition on an external drive with multiple ...
5
votes
3answers
5k views

Is there a good drive torture test tool?

I have been having odd and rare filesystem corruption lately that I suspect is the fault of my SSD. I am looking for a good drive torture test tool. Something that can write to the whole disk, then ...
2
votes
0answers
140 views

Block Devices & Partitions

I partitioned a microSD card (mmcblk1) into two partitions mmcblk1p1 and mmcblk1p2. If use a dedicated card reader I am able to see the entire SD card and its partitions using various disk management ...
2
votes
1answer
164 views

Keeping disk caches when hibernating

Is there a way to keep disk caches when hibernating Linux? I understand and agree that dropping them is the best option all-around. But my system is unresponsive after resume and I would like to give ...
13
votes
3answers
708 views

Horrible situation - file systems mounted simultaneously by multiple independent OS instances

How do I get out of this situation safely? Details are as follow: A xen server has got block devices allocated to VMs. But these devices have also been mounted inside Xen. In fact 44 of these ...
1
vote
0answers
37 views

Reasons for choosing primary over logical partitions [duplicate]

I guess anyone knows the benefits of logical volumes. But are there any reasons why I should choose primary partitions if I can?
2
votes
2answers
900 views

Can't format external drive

I am trying to format an external drive, but getting the error /dev/sdb1 is apparently in use by the system; will not make a filesystem here! Based on the internet, I have to run cat ...
1
vote
1answer
92 views

Really umount external drive

I had a USB drive mounted on /dev/sdb1 and I want to reformat from NTFS to ext3. I did umount -l which unmounted the disk. I deleted the old partition using cfdisk. I ran mkfs.ext3, but got the error: ...
1
vote
1answer
4k views

UUID Of A drive that won't show up in /dev/disk/by-uuid or blkid

I have a USB drive that is not receiving a UUID. When I look at the contents of the /dev/disk/by-uuid it doesn't exist there. The dev point that the partition lives in is on /dev/sdb. I am able to ...
4
votes
2answers
4k views

Linux Mint freezes on startup

Premise I am running Linux Mint on my sister's computer. Everything was working fine, but than one day she turned it on and she got a strange message she didn't understand. I think it was some kind ...
1
vote
2answers
1k views

Using SAR to monitor free disk space data

Is there a way to make sar (from sysstat) collect free disk space data?
2
votes
3answers
4k views

Can I create a software RAID 1 with one device

I have a single disk that I want to create a Mirror of, Lets call this disk sda I have just bought another identicle size disk, which we can call sdb. sda and sdb have one partition called sda1 and ...
1
vote
0answers
1k views

How to set up ZFS with ZIL and L2ARC SSD?

I have been considering bcache and flashcache. However my friend suggested me something called ZFS. In fact it says that formating disk with ZFS can actually do the exact same thing without kernel ...
1
vote
3answers
117 views

Bad sector on a directory

I've a bad sector on my /home/xyz which make a folder with 10 GB data unreadable. As far as I can see in syslog there's only one badsector with may destruct 4K of data while I have no access to 10 GB ...
14
votes
8answers
9k views

How to determine which sd* is usb? [duplicate]

Possible Duplicate: How to know if /dev/sdX is a connected USB or HDD? The output of ls /dev/sd* on my system is - sda sda1 sda2 sda3 sda4 sda5 sda6 sda7 sdb sdc sdc1 sdc2 ...
2
votes
2answers
135 views

Why I have two /dev/sdx entries with a single disk?

In my laptop (running Linux) I have only one SSD, connected to the SATA3 port. Why I have two sdx entries in /dev directory? In particular I see /dev/sda and /dev/sdb, and /dev/sda is the SSD: # ...
4
votes
1answer
9k views

/dev/sdb: No such file or directory (but /dev/sdb1 etc. exist)

I'm not sure what is wrong here but when running fdisk -l I don't get an output, and when running fdisk /dev/sdb # I get this fdisk: unable to open /dev/sdb: No such file or directory I'm ...
4
votes
2answers
161 views

Determine which process is taking most of disk bandwidth?

When the HDD indicator is blinking (for a long period), how could I know which process is taking most disk bandwidth?
40
votes
7answers
71k views

How can I monitor disk io?

I'd like to do some general disk io monitoring on a debian linux server. What are the tools I should know about that monitor disk io so I can see if a disk's performance is maxed out or spikes at ...
2
votes
2answers
738 views

RHEL 5.5 - Need to refresh /dev/disk/by-label links

I've added a fibrechannel disk to a RHEL 5.5 server. The disk is present and shows under /dev/sdxx - But I need to give udev a kick and have it refresh the /dev/disk/by-label/LABEL links; this is ...
0
votes
1answer
1k views

Resize non-LVM ext4 root partition

How can I shrink/resize a non-LVM ext4 root partition? The problem is I can't unmount it and I don't have physical access.
0
votes
1answer
650 views

How to resize root Volume Group

How Can I reduce size of root volume group? /dev/VolGroup00/LogVol00 I just have SSH access to Linux host.
3
votes
0answers
202 views

Setup Cloudmin on Centos installed in LVM

I installed CentOS 6 with default LVM partition pattern. according to this pattern Can I use Cloudmin and store KVM Disks in LVM as Logical Volume? I think Cloudmin requires creating new logical ...
2
votes
1answer
4k views

Unable to create logical partition with Parted

I was fiddling around with parted command on a loopback disk and tried to create some partitions using gpt part table but I keep getting Error: Unable to satisfy all constraints on the partition. when ...
3
votes
3answers
612 views

Disk size management

I am using Fedora 16. My /dev/sda2, mounted on / (root) with something like 50G got filled 100%: [foampile@~ 13:13:39]> df Filesystem 1K-blocks Used Available Use% Mounted on rootfs ...
8
votes
3answers
422 views

Physically break into box? (Memory & disk)

I have a VPS. I might be able to encrypt my partition but I havent tried. My VPS company I believe can reset my root password although the only SSH key I see is my own. With all my data I have it ...
3
votes
1answer
3k views

recovering ext4 partition after dd'ing over start of HD

I accidentally used dd and wrote over the first 208MB of my external disk. What I wrote over is a partition on its own (Debian nestinstaller) so what I see now is not my old (now damaged) ext4 ...
4
votes
3answers
4k views

Is it safe to resize partition on /?

I currently have a 600gb disk, with Ubuntu installed, 600gb of which is given to the Ubuntu OS: Filesystem Size Used Avail Use% Mounted on /dev/sda1 592G 16G 547G 3% / udev ...
3
votes
2answers
79 views

How to get size of data that haven't been written to disk yet?

In some programs percentage of copying large files get to 100% very fast and then I'm waiting much more before it goes next step. It's caused by buffer. How to I see amount of data that are going to ...
3
votes
2answers
854 views

What could cause a NAS mount to respond slowly?

I've a directory on a NAS mount (from NetApp), that contains ~6300 image files, total size of this directory is ~ 300 MB. I get two different performances of time ls: First time (or after waiting 5-7 ...
21
votes
3answers
15k views

How can I safely remove a SATA disk from a running system?

I sometimes need to plug a disk into a disk bay. At other times, I have the very weird setup of connecting a SSD using a SATA-eSATA cable on my laptop while pulling power from a desktop. How can I ...