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

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1answer
14 views

Problem creating raw disk image and mounting it in rescue mode to QEMU

I am trying to create booting system from raw disk image. This is what I do: $ dd if=/dev/zero of=system2.img bs=1M count=6000 6000+0 records in 6000+0 records out 6291456000 bytes (6.3 GB) copied, ...
82
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26answers
108 views

Tracking down where disk space has gone on Linux?

When administering Linux systems I often find myself struggling to track down the culprit after a partition goes full. I normally use du / | sort -nr but on a large filesystem this takes a long time ...
1
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1answer
41 views

How to find the true disk usage on my Linux box?

I have a linux box on my school's server. When I was trying to install Protocol Buffers, disk usage is reported as exceeded. So I checked my disk usage by two command on my home directory: du -h ...
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0answers
14 views

Install system to Disk on Chip

I'm looking for an easy way to install linux on a PC104 (x86 no cmov) system with a Disk-on-Chip. It can be a very simple system (BusyBox, etc) or a distro the installs in under 512mb. I just need to ...
1
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0answers
4 views

Unable to open Windows Disk partitions in solaris 11 [duplicate]

I have recently installed solaris 11, but I am an absolute beginner in unix systems. The only unix like environment I have got myself into before is ubuntu which was quite a bit different from solaris ...
2
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1answer
324 views

Expanding the disk size on pfsense under VMWare ESXi

I've been testing pfsense on ESXi for a while. And now I'm almost running out of space. Currently it holds around 30GB and I would like to expand it to 150GB as I'm planning on installing squid for ...
1
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2answers
18 views

start qemu by giving it a path to a linux root

Good evening, I installed ArchLinux on a USB stick, and I would like to boot it in qemu. Unfortunately, most examples I found boot an image (iso..). The stick is definitely bootable as if I restart ...
28
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7answers
35k 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 ...
4
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2answers
300 views

How does Linux md-RAID handle disk read errors?

There are 2 cases: the read command times out at kernel level (30 seconds by default), the drive reports its unability to read a given sector before the kernel lose patience (the case I'm ...
1
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2answers
53 views

Disk on key is read only on every computer

I have a 16 GB SanDisk Cruzer Blade Disk-on-key. After a few days of use, it has become write-protected/read-only. When I plug it in, you can see this in my Ubuntu's dmesg: [ 819.003359] usb 2-5: ...
2
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0answers
33 views

The proper way to turn off an external sata encolsure?

I have an e-sata external enclosure with a port expander and 4 sata disks in it that I use for periodic backups. I have what I think is a sound method for powering it off, but not sure if it is the ...
13
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8answers
4k 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
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3answers
200 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
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3answers
167 views

/dev/disk/by-uuid/ not working on one machine

I have a iSCSI disk which I am mounting from several machines (exclusively, not concurrently). On machine A, I start iscsi service open-iscsi start and the iscsi disk is discovered as /dev/sdb1. ...
0
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2answers
76 views

How to get total disk read/write in bytes per hdd device from /proc

How to get total disk read/write in bytes per hdd device? for example if i have sda, sdb, and sdc, is there any file on /proc that i could use similar to /proc/net/dev for networking?
2
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1answer
53 views

libata patch to allow disable sata port

My question is related to the patch introduced in this post How to tell Linux Kernel > 3.0 to completely ignore a failing disk? If the kernel is patched with this code what is the kernel parameter ...
-1
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1answer
52 views

What is a file? [closed]

I thought that the file is a reserved place on disk and it is a Record collection but i found that it is a wrong definition because the empty file capacity is 0kb so it can't be a reserved place on ...
3
votes
0answers
29 views

Unable to close a Luks partition

For backup purposes, I have "snapshotted" a LVM partition. This partition was crypted so I have opened this Luks partition (snapshot) in order to do my backup. The problem is that I have forgotten to ...
10
votes
3answers
606 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 ...
6
votes
4answers
456 views

Given a kernel ATA exception, how to determine which physical disk is affected?

I woke up this morning to a notification email with some rather disturbing system log entries. Dec 2 04:27:01 yeono kernel: [459438.816058] ata2.00: exception Emask 0x0 SAct 0xf SErr 0x0 action 0x6 ...
4
votes
1answer
97 views

Edit file on image created with dd [duplicate]

I've a bootable USB with Debian. Normally I clone the disk with dd, write the image on a new USB disk, mount this disk on my filesystem and edit some files. Is it possible to edit files on the image ...
0
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1answer
55 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 ...
2
votes
4answers
124 views

What is the /dev/disk/by-uuid/ and why does it use all free space on the disk

I have the following Debian that works in Virtual Box: $ uname -a Linux debian 3.2.0-4-amd64 #1 SMP Debian 3.2.51-1 x86_64 GNU/Linux Recently I notice that I don't have any free space: $ df ...
5
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2answers
150 views

How to create a fixed size Linux ramdisk which does never swap to disk?

I want to create a fixed size Linux ramdisk which never swaps to disk. Note that my question is not "why" I want to do this (let say, for example, that it's for an educative purpose or for research): ...
0
votes
1answer
44 views

Is there something wrong with df output? [duplicate]

I'm using the command df -h to check disk usage on CentOS 6.4. I see an inconsistency with the output. look at the line Filesystem: total 490Gb, used 55Gb, and Available 411Gb. What is it mean? I ...
4
votes
1answer
5k 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 ...
2
votes
1answer
124 views

Mounting another VM's .vdi in VirtualBox

I have two VMs in VirtualBox. For exmaple, VM 1 runs Red Hat, and VM 2 runs Ubuntu. For the Red Hat VM I have redhat.vdi and redhat2.vdi, and for the Ubuntu VM I have ubuntu.vdi and unbuntu2.vdi. ...
3
votes
2answers
41 views

Uniquely identifying a drive (not a partition)

I'm writing some automation scripts for full disk backups and I'd like to be fairly precise with which devices are used. I know that one can uniquely identify a partition using UUIDs and blkid, but ...
2
votes
2answers
103 views

How do I navigate to a CD drive?

I'm trying to install Virtualbox Guest Additions in Elementary OS. cd doesn't seem to work with cd VBOXADDITIONS_4.2.6_82870. Update: I did what @ivica recommended, and here's what I'm getting: I ...
0
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1answer
45 views

How to create memory-based disk in linux? [duplicate]

I need to have a very fast disk for keeping cache. How can I do that in Linux?
2
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1answer
161 views

Difference between “blockdev --flushbufs” and “sync” on Linux?

Is there a difference in practice between running blockdev --flushbufs and sync(1) on Linux? (apart from blockdev flushing for a specific device, and sync being system-wide). sync(1) manpage says it ...
2
votes
2answers
347 views

Free space: 0 bytes and files full of data shown as empty

I don't know what's going on. The last evening I left my computer with about 700MB of free space on the system partition and today there is no free space on disk, moreover a lot of files containing ...
1
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1answer
50 views

Repartion multiple disks and reallocate storage

I’m trying to re-partition from an Arch Linux install disc. I’m doing so because my current OS is corrupted. When running fdisk –l this is what it looks like: /dev/sda1 * start=2048 end=1026047 ...
3
votes
2answers
660 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
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0answers
113 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 ...
6
votes
2answers
261 views

Creating formatted partition from nothing

I need to create filesystem with just one partition from nothing (/dev/zero). I tried this sequence of commands: dd if=/dev/zero of=mountedImage.img bs=512 count=131072 fdisk mountedImage.img n ...
1
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3answers
107 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 ...
1
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1answer
232 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 ...
5
votes
3answers
3k 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 ...
17
votes
3answers
9k 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 ...
2
votes
2answers
311 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
658 views

Using SAR to monitor free disk space data

Is there a way to make sar (from sysstat) collect free disk space data?
11
votes
2answers
410 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
260 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
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1answer
75 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 ...
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2answers
224 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 ...
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2answers
52 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 ...
3
votes
2answers
636 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 ...
0
votes
3answers
207 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
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1answer
186 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 ...