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Questions tagged [disk]

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

5
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0answers
181 views

“leaky bucket” style disk io throttling using linux kernel

My goal is to prevent one kvm guest's disk i/o usage from negatively affecting other kvm guests on the same host. The host has one disk array - and separating guests onto different physical disks is ...
4
votes
0answers
2k views

Cannot mount, read, write, or format SD Card

I can read from my micro-sd card when it is in "lock" position but things get very weird when I try "unlock" it: there is no way I can fsck it, nor mount it, nor read it, nor.. format it! I need ...
4
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0answers
2k views

Disk I/O latency using /proc/vmstat file

How do I calculate disk read and write latency in Linux? Is it possible to do the calculation using /proc file system? I am using iostat and vmstat command. But I do not understand how the ...
3
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0answers
152 views

Root device has 2.9GB disk space free, but throws disk full errors

Here's some console output below to illustrate the problem. I was able to work around this by clearing out old packages which gave me 4.6GB free, but I wanted to pose this question here out of ...
3
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0answers
203 views

Linux drive not being read anywhere

I installed Manjaro Linux on my new 128GB M.2 SSD. It was all working fine for a week or so. I was then deleting some large files (4+GB) from another 2TB HDD. Each of these deletions took about a ...
3
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0answers
54 views

Looking for special files by minor number and major number

Is it possible to use find command (or anyone else) in order to look for special devices (like disks) passing minor/major number? I thought something like this: find / -type c -minor 30 -major 29 ...
3
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0answers
132 views

monitoring block access to disk

I am looking for a way to monitor access to disk blocks, and to monitor the access as a bitmap of blocks. I also need the capability to freeze (and queue) the device block access (and also to ...
3
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0answers
109 views

Use a “Friendly” Label on Drives or Partitions in FreeBSD

Maybe I am missing this and it's really simple, but I cannot figure out how to label a BSD disk. I have looked at tunefs or gpart and even disklabel, however none do what I am looking for - I don't ...
3
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0answers
940 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 ...
2
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0answers
83 views

/sys/block/sd*/device/timeout not accurate

The default value for the timeout file for SCSI disks is 30, supposedly meaning 30s. In my dmesg logs, I find that the system is waiting 180s before timing out. Setting timeout to various values ...
2
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0answers
143 views

Disable writeback cache throttling - tuning vm.dirty_ratio

I have a workload with extremely high write burst rates for short periods of times. The target disks are rather slow, but I have plenty of RAM and very tolerant to instantaneous data loss. I've ...
2
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0answers
67 views

Available disk space drops, while used space stays almost still

Recently I found out that on one of my servers (Ubuntu 16.04) I get significant drops on free disk space, at nights: zooming to the last 1h (from right now): one can see this happens abruptly. Just ...
2
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0answers
43 views

Prompt user with email when Disk Usage is over 200GB

find . -printf "%u %s\n" | awk '{user[$1]+=$2}; END{ for( i in user) print i " " user[i]}' Hi I have been using the above CMDline to look for each user's disk usage information. I would like to know ...
2
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0answers
115 views

Receiving a lot of errors from /dev/sda

I have an Asus EeeBox PC - B204( original specs here: https://en.wikipedia.org/wiki/Asus_EeeBox_PC ) running Ubuntu 14.04.5 LTS; The only thing changed was the original hdd to a Kingston V300 SSD; ...
2
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0answers
264 views

Priority read and write files

Good day, I had a question that I could not find the answer. I tested my hard drive, mounted on /media/data using dd. Some simple scripts: write: echo "3" > /proc/sys/vm/drop_caches for i in {1....
2
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0answers
125 views

unix c-shell : disk checking

im totally new in shell scripting. I have task to simplify an old c shell script. Basically, the script have 10 devices that using hp-ux and i want to check the disk space in each devices. my ...
2
votes
0answers
179 views

GNOME Disks Sample Size

I'm trying to use GNOME Disks to test my disk performance and, according to my previous experience, I'd like to set the sample size to 8K, 16K and 32K. However, I see the minimal sample size in its ...
2
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0answers
730 views

LVM partition not mounting

There was a drive failure on a disk in a RAID1 configuration. I removed the bad disk and reconfigured the RAID1 to only use the good disk. When I reboot the machine there are missing LVM partitions. ...
2
votes
0answers
388 views

View syscalls/kernel activity for I/O from a running process

I'd like to be able to view syscalls or kernel activity for a process...I'm not actually sure of the terminology I need here! Specifically I'm looking for the difference between I/O going to local ...
2
votes
0answers
2k views

How do I get ata-style IDs in /dev/disk/by-id to work for USB disks?

I have USB drive dock that I'm plugging SATA drives into. The way they show up in /dev/disk/by-id seems to be dependent on whether the drive has a partition table (usb if not, ata if yes). This makes ...
2
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0answers
309 views

SMART extended offline test validity

Is it possible for the smartctl -t long /dev/sda to complete without error and still the drive fail? How detrimental to the disk's life expectancy is running the test daily/weekly? Thanks!
2
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0answers
721 views

midnight commander: rules for accessing archives through VFS

Midnight Commander uses virtual filesystem (VFS) for displying files, such as contents of a .tar.gz archive, or of .iso image. This is configured in mc.ext with rules such as this one (Open is Enter, ...
2
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0answers
325 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
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0answers
355 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 ...
1
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0answers
92 views

How to exclude a directory or partition on pmlogger scan?

As on the details below it look like that the cause of the problem is the pmlogger is spawning the find command. And its takes a long time for the find to scan all the files in one of my partition. ...
1
vote
0answers
49 views

Cannot access mounted partition after using dd

I have used following command to create an image of mounted partition sda1: dd if=/dev/sda1 of=/dev/sdb1 'conv=noerror,sync' where sda1 is the one I want to "backup" and sdb1 is obviously target, ...
1
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0answers
39 views

What is writing/reading to a mounted share in a VirtualBox Linux guest

I have a Linux guest running on a Windows 10 machine in VirtualBox. One NTFS-drive of the host has a directory shared with the Linux guest via the "Shared Folders" configuration Machine Folders -> ...
1
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0answers
786 views

Ext4 with LUKS explorer for Windows

What is the easiest way to use an external drive with LUKS encryption and EXT4 file system in Windows ? Ext2read have support for LUKS ?
1
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0answers
24 views

Does the system use the space on the hard disk which has never been written on, before over-writing the deleted files?

Suppose the total capacity of the hard disk is 1 TB but the user always uses about 500 GB. While allocating new space, does the system give preference to the never used space or overwrites deleted ...
1
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0answers
88 views

Disks aren't showing in /dev/sdX

I got a 2nd SSD installed in my system, and for some reason it's not showing up in /dev/sdX nor is it being shown as a mountable drive. The partitions and the disk exist, but for some reason Linux ...
1
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0answers
357 views

How should I partition a 250 GB SSD for my laptop?

I'm replacing my laptop's HDD with a 250 GB SSD. Right now, the laptop has just one partition mounted on / (on a 228 GB HDD). I could just do the exact same thing, but on desktops I'm used to do ...
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0answers
28 views

Read and Write Disk Drive registers as Read Only

I am having an issue were my read write disk drive is being registered by my system as "Read Only" I know its capable of burning disks because its done it before when it ran on my previous OS. How do ...
1
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0answers
95 views

NMVe SSD Fedora Throughput Tests too High

I am testing throughput of a Samsung 950 Pro SSD Card which uses NVMe protocol. My current method of testing is to mount a file system on a partition and write a file of size X bytes to the file ...
1
vote
0answers
2k views

How to fix corrupt GPT table backup?

I'm having an issue which I'm having a hard time trying to fix with a USB stick. I was trying to get this USB formatted cleanly and ready to be used for a USB Installer, but for some reason it's ...
1
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0answers
827 views

vmware centos7 disk full?

I have already executed reboot, why is my disk still full? OS: CentOS7 at vmware df -h [root@localhost swoole_http_server]# df -h Filesystem Size Used Avail Use% Mounted on /dev/mapper/...
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0answers
273 views

Eject (not unmount) USB devices via terminal (SSH), and redetect a USB device after ejecting

This is a macOS question (Unix), and since Ask Different doesn't have many savvy terminal users I am asking here. Other than right click the device and select eject (this is not unmount, because it ...
1
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0answers
39 views

Two entries for each disk on hba

I see two device entries (ie. /dev/sdaa and /dev/sdab ) for each disk in my Quanta M4600H. The HBA is an LSI SAS2308. I assume this is happening because of the two SAS connectors the HBA utilizes. ...
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0answers
73 views

Disk I/O degradation with concurrent writes to the same file

I am benchmarking concurrent disk I/O from multiple processes, and I get very different results when writing to the same file, or to different files. Because I am using O_DIRECT, I was not expecting ...
1
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0answers
68 views

Relation between write and filesystem blocksize in SSD disks on Apple

R. Stevens, in his famous book about programming in O.S. environment, taught us that when the syscall write's block size is comparable (or even equal) to the filesystem block size, the performances ...
1
vote
0answers
67 views

How to find hard drives by size or model?

In FreeBSD, what is the correct way to find hard disk drives by some criteria, like size or model name (ok, here /dev/disk/by-id would help if one had it, as usually in Linux)? For example in FreeBSD ...
1
vote
0answers
54 views

Strange df output after ddrescue clone

My old harddisk was having I/O error last week so I tried to copy the data out to another new disk intending to rescue the data. I use ddrescue: ddrescue -f /dev/sda1 /dev/sdb1 my_mapfile After I ...
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0answers
11 views

How to log process that accesses disk for longer than 5 seconds continously?

Sometimes disk spins up when computer is inactive and it lasts and lasts and lasts. I have no idea how to figure out what it is. Usually I notice this while lying down and by the time I get there and ...
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0answers
243 views

Antergos Install

I have always had trouble installing Antergos. One time, after messing around for days, the installer completed and I was able to have Antergos on my system. Now I have an SSD and I want to transfer ...
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0answers
5k views

How to change disk name from /dev/sda1 to /dev/sd127 in ubuntu

How do I change the name of the disk in ubuntu 14.04 LTS server from /dev/sda1 to something else like /dev/sd127? This is a regular EXT4 striped disk attached to the system.
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0answers
168 views

Does dstat captures disk i/o by the OS prefetching?

I ran a program which sequentially reads a big file. The transfer rate [MB/sec] is strictly controlled by the application as 5MB/sec. However, when I monitored the disk i/o bandwidth usage using ...
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0answers
610 views

Why is systemd-journald doing some massive disk writes?

For some reason my computer shut down recently. I have also fairly recently done a pacman -Syu to upgrade all the things. However, now systemd-journald is doing a massive amount of disk writes - like ...
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0answers
302 views

Extending XFS filesystem CentOS 7 Google Cloud

I have Googled everything, and literally nothing is working. Here is df -h: Filesystem Size Used Avail Use% Mounted on /dev/sda1 10G 7.7G 2.4G 77% / devtmpfs 103G 0 103G ...
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0answers
310 views

Reclaiming disk space in Ubuntu

In VMWare the hard disks took 13.6 GB, But with df, only 5.8 GB is occupied I don't quite get it. This Virtual Machine has no snapshots, and I already clicked on refresh button in VMWare Fusion Is ...
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0answers
244 views

Random write on DISK benchmark shows high read rate on iostat

I am running a random write benchmark directly on some disks (HDD & SDD) and I am getting some weird output data on the iostat monitor. Besides the usual write rate, there is a read rate that I ...
1
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0answers
105 views

iostat ( column svctm is not trusted any more ) what to use instead?

I'm running a Linux Server with "Oracle Linux Server release 6.5" which is pretty much the same as RedHat Version. I need to determine the latency on my disk devices. The man page of the iostat ...