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

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1answer
719 views

CentOS 5 - hdparm - how to set DMA mode

I'm running CentOS 5 with a PATA hard drive. I've used hdparm to tune the hard disk for better performance, but there are 2 settings that don't work: hdparm -M 254 /dev/hda gives the error ...
2
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1answer
891 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, ...
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1answer
63 views

Deleted boot partition accidentally with gpart

I just typed gpart delete -i 1 ada0 when I was supposed to write gpart delete -i 1 ada1 and unfortunately typed reboot before I noticed my mistake. The disk ada0 had the default GPT layout that ...
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1answer
76 views

Disk numbering a drive then mounting in solaris 10

I've a rescued sun v240 (2x 73Gb scsi drives). Trying my best to get onto the Solaris 10 OS. Managed to get via console lead and putty on windows machine . Managed to get cdrom-s single user (used ...
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1answer
180 views

Very slow file operation

I recently rebuild a machine with Centos 5.8 with a brand new disk. This machine is old and has been running 5.8 for a long period with no issues so the only thing which changed recently is the new ...
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1answer
142 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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1answer
77 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 ...
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1answer
26 views

inconsistency between format and probe-scsi-all outputs

my platform: SPARC T4-1 Generic_150400-24 sun4v sparc sun4v 1 of the disk is seems different in the output of format when I am on console cli even though relevant disk seems same as others in the ...
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0answers
722 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 ...
3
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0answers
276 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 ...
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0answers
24 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 ...
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29 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 ...
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0answers
83 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. ...
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0answers
192 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 ...
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0answers
105 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 ...
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0answers
530 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 ...
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0answers
132 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!
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0answers
245 views

expanding boot, moving LUKS root

GPT > Partition2 > LUKS > btrfs I need some additional space for my boot volume, so far I did: Shrink my btrfs volume by 250MB. btrfs resize -250M / Shrink the LUKS root volume cryptsetup ...
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0answers
449 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 ...
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0answers
204 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 ...
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16 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 ...
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0answers
20 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 ...
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44 views

sysv and unknown partition table?

We have disk about 1985, It has a Unix.But we didn't know type of Unix.I did the following step : dd if=/dev/sdc of./all_of_disk.iso #sdc is the given disk Then : hexdump -C all_of_disk.iso > ...
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0answers
59 views

List partition type GUID's for all disks from command line?

I need to list the partition type GUID's from the command line. Note: This is not the same as the partition UUID. Basically I'm needing to search for all disks that have the Ceph OSD type GUID: ...
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96 views

Disk configuration options, what can affect performance

I have 2 disks, the same model and vendor, first one , probably performs faster. We do write into multiple files. Can you compare 2 configurations and tell what can affect performance? 1. (faster) ...
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130 views

How can I get read/write instant speed of a Hard Drive using /proc/diskstats data?

I know that the proc/diskstats file presents these data columns: 1 - major number 2 - minor mumber 3 - device name 4 - reads completed successfully 5 - reads merged 6 - sectors read 7 - time spent ...
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0answers
134 views

Flash memory and set to read only , Is it virus?

Becuase some of limitation of MS.Windows, my friends and my family gime their flash memory to solve their problem. Such as format, partitioning in Linux with the cfidsk ,parted, sfidsk(dump and ...
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144 views

Separating SAS from SATA drives

I have to list all SAS drives and separately list all SATA drives, I'm working on CentOS6 and tried lots of commands which will give some specific information about bus of disks. Let me show you ...
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0answers
74 views

Shared NTFS partition conflict, files written under Debian gone

I have a dual-boot W7-Debian Jessie on my laptop, and a NTFS partition initially left for sharing data between OS and keeping big files. With myself getting used to Linux, rebooting to windows became ...
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35 views

Disk copying with two OS on it

I want to change HDD in my laptop to bigger one. I have installed WIN XP and Mageia Linux and GRUB ver 1 as bootloader. So I want to use such procedure for copying and changing disk: plug new one ...
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0answers
360 views

Monitoring Disk Latency

We have quite a few physical machines in our environment, yet we have no trending data over a period of time for disk latency statistics. We can easily run the standard iostat commands to see what the ...
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0answers
190 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, ...
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0answers
67 views

Edit partition of disk part of a ZFS Raid

I've gota strange problem. Since a previous failure from one of my hard drive, I had to replace one of my 4 hdd running in RAIDZ. But since I changed this disk, the last partition of my disk appear ...
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0answers
22 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 ...
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0answers
277 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 ...
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0answers
2k 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 ...
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29 views

Can't boot into my Linux partition--disk is supposedly at fault, but scans show no errors

I'm trying to boot into my Linux partition, but receive this message: Welcome to emergency mode! After logging in, type "journalctl -xb" to view system logs, "systemctl reboot" to reboot, "systemctl ...
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9 views

why does SCSI Host value change during reboot?

I have attached a virtual disk to my VM and the Host value changes during reboot. How can we bind it to a particular value? Host: scsi2 Channel: 00 Id: 00 Lun: 00 or Host: scsi3 Channel: 00 Id: 00 ...
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99 views

how can I see the uuid of a disk in my system WHEN IS NOT LISTED IN /dev/disk/by-uuid

I have a problem in my system, that I don't understand: there are no disks UUIDs, only partitions UUIDs: ls -al /dev/disk/by-uuid/ total 0 drwxrwxrwx 2 root root 140 Nov 21 20:36 ./ drwxrwxrwx 5 root ...
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24 views

SSD as write target during reads

I have a real-time application which always writes data to a RAID 10 HDD configuration in a sequential manner at around ~50 MB/s. It uses mmap and writing should never be blocked due to waiting I/O. ...
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33 views

How do I interpret GNOME Disks' benchmark results?

Having ordered a new USB drive for my parents, I decided to use the Benchmark option in GNOME Disks. The results were interesting: A third run with a sample size (odd phrasing!) of 100 MB gave ...
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55 views

CloneZilla, does exist a simpler method?

While browsing the web for backing up my disk, I often see CloneZilla in the results. As a beginner with Linux, the process seems tricky to me (Live USB, etc). Note: I plan to back up my whole disk ...
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49 views

How do I identify which disk(s) make up a vxfs disk group?

In case it matters, system in question is Solaris installed on SPARC. System contains two HDDs, same make/model/capacity. On one HDD are the root and var partitions/slices. /etc/mnttab shows me that ...
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0answers
157 views

/proc/diskstats and iostat are right? strange values on my test

My question is quite simple.. I am doing some tests to confirm the perfect work of both (diskstats and iostat) disk meters and something is wrong here. I write this command on cmd and I get the ...
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27 views

Add Disk Google Cloud

Sorry by my english. I have this situation: 1.create a instance, in google, this load with 10GB. 2.add (in google cloud) a disk persistent with 200Gb I need save all my websites in the disk ...
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280 views

How do I decrypt this hard drive?

In 2011 I installed Ubuntu server edition on an old Dell that I had laying around. During the install process I was using the gui installer and opted to set disk encryption on the disk drive. During ...
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0answers
31 views

How to prepare for a possible unreadable disk from bios after swapping disks?

How to prepare for a possible unreadable disk from bios after swapping disks? I want to switch out my old disk with my working linux mint 16 os and plug in a new disk and install linux mint 17. I am ...
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89 views

Any tool or command can detect flash disk or SSD memory type?

Here I mean "SLC" or "MLC", basically, how many bits per cell for the NAND memory. Is there anything we can get? Thanks.
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37 views

Why does reading from a symlink to network location cause local disk activity?

I am running RHEL 6.4 and have a symbolic link in my home directory to a large file stored elsewhere on a network. My home directory is a network location as well. I've noticed that when I run a ...
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0answers
135 views

AIX equivalent of Solaris' iostat -E

On Solaris you can use the command iostat -En to view "disk error statistics" as counted by the kernel since the last reboot, where the -n option causes iostat to show "nice" device names. I'm ...