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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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Multi-Generation Snapshots using Device Mapper (Linux)

LVM is an amazingly useful tool, however, it seems to still lack support for snapshotting a drive that is already a snapshot. I made a script to handle this automatically but ran into some troubles. My test environment I'm testing the script on a…
st0ne2thedge
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Are blocks that are read from LVM kept in Linux's block cache?

Does Linux keep blocks that are read from an LVM logical volume in the block cache as it does with blocks read from a "regular" block device or is the IO direct? Also, do the usual buffering semantics apply for writing to a logical volume?
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export block device over network without root

I'm trying to export a file as a block device over the network. I do not have root access on the machine where the file exists. I do have root access on the machine(s) where I will mount the block device. I've seen ATA-Over-Ethernet and ISCSI but…
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Using MySQL raw disk on Windows?

I'm having trouble getting MySQL 5.7 to use raw disk (a block device, bypassing the filesystem) for its data. My understanding of the documentation is that basically, first time mysqld is executed, the config needs to have the newraw keyword in the…
myxal
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Doesn't file storage rely on block storage?

I'm usually working on software and am weak on storage. I'm reading about block vs file vs object storage and everything I find talks about storage as an entirely isolated subject rather than including what the operating system would see - which is…
Grant Curell
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Looking for a NBD C/S for windows (Network Block Device)

Where can I find a NBD Server (and also a Client) that I can use in windows 10? (preferably FOSS source code for inspect/change/compile/...) Been looking for a while on the internet and seems that no one overcome this task...
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Dont use /dev/sd* for removable device

Today I almost erased my system with dd because I was going to write on my internal HDD (/dev/sdb*) instead of the removable usb (/dev/sdc*). I want to make a udev rule to set any block usb under a completely different name, like /dev/remX* Where X…
Lesto
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Btrfs check repair give device busy. How to see what it keeps busy?

I am in a chicken-egg situation for my secondary harddrive (non boot): My BTRFS mount has gone readonly because no space left. btrfs filesystem resize only works on mounted volumes. I needed to umount this ro mount in force mode (because of device…
robert
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Read Ahead value automatically getting updated at boot

OS version: CentOS Linux release 7.2.1511 (Core) I have the following commands in my rc.local file: /usr/sbin/blockdev --report > /root/test_boot /usr/sbin/blockdev --setra 256 /dev/vdb /usr/sbin/blockdev --report >> /root/test_boot After booting…
Shikhar Awasthi
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USB Mass Storage recognized, but SCSI block-device not showing up

The block-device of a USB mass storage does not show up in Ubuntu 16.04, while I positively can see it in Ubuntu 14.04. Question: How can I make it show up in Ubuntu 16.04? NOTES: Both machines are virtual on the same hardware, so it is not…
Xavi Montero
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Why is an EC2 AWS instance showing an extra block device?

I'm using aws cli's autoscaling to create EC2 instances. Despite only having two device mappings in my launch config, the resulting instances have an additional device. The pertinent map Json: "BlockDeviceMappings": [ { "DeviceName":…
AXE Labs
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Proper way to identify member devices in mdadm.conf

My current mdadm.conf looks like: $ cat /etc/mdadm/mdadm.conf DEVICE /dev/sdb1 /dev/sdc1 ARRAY /dev/md0 metadata=1.2 spares=0 UUID=357ff7cc:55e78d18:9fc7917b:f5b253f2 MAILADDR me@example.com Since upgrading the kernel from a 2.6.x to some 3.x, I…
davide
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Is there a way of relating the RAID units with the OS devices in 3ware?

I got a Linux server recently with a 3ware RAID. It has several volumes (/c4/u*/v*) that are seen by the OS as devices (/dev/sd*) I can roughly relate those units with the devices because of their size and some other characteristics. Is there a…
nsn
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XenServer move VM Failed

We currently are running our XenServer virtual machines off of an over extended Drobo unit and wanted to migrate a particular 600+GB VM off of the Drobo onto a newer Drobo, so I attached a storage repository on the new Drobo and used the XenServer…
Riley
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How to auto mount 2nd drive on boot in Windows Azure on linux?

I'm currently programming a website and it's connecting to Ubuntu 12.04 linux VM on Windows Azure for database connections. The issue I'm having is that if the VM is restarted the attached disk I added for the db data files does not auto mount after…
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