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Questions tagged [block-device]

Block devices are a specific type of Unix device node, typically representing storage devices such as hard drives, CD-ROMs, etc.

Block devices are a specific type of Unix device node which the operating system reads from and/or writes to in blocks of data -- typically a multiple of 512 bytes.

Some common block devices are hard drives and CD-ROM systems.

Traditionally block devices have been cached by the operating system. As this caching can lead to undesirable behavior a "raw" block device is typically also provided.

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Possible to set size of ram disk?

When I do yum install MAKEDEV MAKEDEV ram fdisk -l /dev/ram I get the that it is 16MB. I am using MAKEDEV to get a block-device instead of tmpfs. Question Is it possible to set it to e.g. 1GB?
Sandra
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Scanning for new disks attached using virtio?

I can successfully attach disks to a running KVM instance using virsh attach-disk... virsh attach-disk node-1 /dev/vg_lunsr/lun1 vdb Disk attached successfully ...but these new devices aren't seen by the guest without a reboot, which almost…
larsks
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FS/disk snapshots (like LVM) with shared cache

On Linux, is there a way to take copy-on-write snapshots of a file system (at the FS, block device, or whatever layer), such that if a copy and another copy/the original are concurrently mounted, the disk cache will be shared as well? I'm currently…
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Factually Btrfs is it suitable for block storage usage?

It exists various storage device, file, block and object based. Some filesystem are dedicated to a kind of device. what about Btrfs ? Here I would like to get some technical facts about Btrfs over a block storage device. Indeed, most of cloud…
bioinfornatics
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I had some drbd (i guess block devices?) on my server, after a crash they are all gone

I am not a sys admin but inherited some servers setup with no documentation in linux. Today the server died in a way it was unresponsive and the VMs running on it down...after a good few hours the server reboot itself, so could ssh to it again but…
Codejoy
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Find mount point by device UUID

I have device UUID like from blkid: /dev/sda1: UUID="5db99adc-11d3-482d-af80-1985dac704b1" TYPE="ext4" PARTUUID="000f2b58-01" I search a tool which I can give 5db99adc-11d3-482d-af80-1985dac704b1, and it should return me the mount point of this…
guettli
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Hard drive not visible during Linux Mint installation

I had successfully installed Linux Mint 19 on my new Dell laptop at work. It was working fine, in general, though it did not shut down properly. I'd seen somewhere a video driver might be responsible, so I used the Driver Manager to switch from…
user42363
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How to tell if linux disk is READ ONLY

I have a sata disk on module which has a hardware switch which can lock the disk from being written in a READ ONLY MODE. Is there a way to tell in software whether or not that switch has been switched to the READ ONLY mode? I've already…
Rusty Weber
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Cannot format a drive once used in a ZFS pool

I have created a ZFS test pool with a drive - now I have pulled thet drive out and want to format it to EXT4 and use it outside of ZFS. I think the pool wasn't properly destroyed. Now when I plug the drive into a different machine running ZFS - the…
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why list of disks not printed with order from sfdisk or fdisk commands

we notice about this problem in last few days on one redhat machine ( version 7.2 ) we notice that order of the disks isn't according to the right order note - sda is the OS instead to get the order from small to end as the following…
shalom
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GCE Persistent Disk block sized writes data integrity

The block size for a SSD Persistent Disk appears to be 4096 bytes. If I write aligned blocks of 4096 bytes directly to the block device (/dev/sdb with O_DIRECT and posix_memalign), are these writes going to be atomic? What I want is for the write…
user389502
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Give a VM access to a whole disk with the least overhead with qemu-kvm

I'm moving a Windows 10 install from dedicated hardware to a KVM VM. The disk (SSD) is being physically moved from the current machine to the VM host machine. Is there a way to just pass the entire existing disk to the VM, as-is? The simple option…
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No w/s in iostat output even though wMB/s is high

I am trying to format a 2 TB SAN based block device (/dev/mapper/mpathb). Even though, mke2fs has been running since over one hour without completing, iostat -z -x -m 10 output in a separate terminal shows a surprising thing: There are no completed…
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Where does blkid get its information from? (/dev/block/ showing up in blkid output)

I have a CentOS 7 box that is acting very strangely. On first boot, typing "blkid" produces: [BurnC7 (2015-12-17 22:00:25) ~]# blkid /dev/block/8:3: UUID="c83f7479-4bc1-44e5-84ae-e38a83e75219" TYPE="ext4" /dev/block/8:2:…
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How to have automatic file system checks for Linux Software Raid?

In a Linux Software raid, what is the best practice for periodically having the filesystems checked? With single drive or hardware raid, tune2fs -c 5 -i 1w /dev/sda1 means check the filesystem every 5 mounts or if it has been a week or more since…
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