Questions tagged [bcache]

Bcache is a Linux kernel block layer cache. It allows one or more fast disk drives such as flash-based solid state drives (SSDs) to act as a cache for one or more slower hard disk drives.

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Convert existing LVM LV to bcache backing device

How do I convert an existing LVM LV to a bcache backing device? The official tool for converting an existing device to bcache is blocks, but it hasn't been updated since December 2014. At a minimum, ...
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Are btrfs reads round-robin or throughput maximising?

Does btrfs prefer to read from a faster device if one is available? My reason for asking: I have a btrfs RAID 1 on spinning rust. I want to use bcache for increased performance, and hope to only ...
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Hardware selection criteria for bcache cache device

I'm looking to buy a SSD (or USB key) for the cache device for a bcache setup. My budget is limited. What is/are the most important metric(s) when selecting a device? 4k Random read 4k Random write ...
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Access bcache backing data without bcache (eg from Windows)

Assuming that the bcache cache device is fully flushed, is it possible to access the data stored in a bcache backing device without bcache? I'd like to have a bcache NTFS partition which is also ...
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bcache: speed optimization

I have read Optimizing bcache I am trying to make this as fast as possible: # This gives around 120 MB/s time head -c 10G /dev/zero |pv > tmp # Simulate that there is not 10 G RAM cache echo 3 | ...
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Replace Bcache Backing Device

Suppose I want to replace the crusty old HDD I'm using as a backing device with a new one. Can I transfer my data to the new device without having to set up.an entirely new bcache?
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Corruption on BCache uppon Kernel Update/Upgrade

After using a write-around bcache on the root device of an old laptop for more than a year (HD + SD card), I finally found out that some severe filesystem corruptions I was facing -- which lead me to ...
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228 views

Add a backing device to an existing bcache device

I currently have a bcache device with one SSD as cache and one HDD as a backing device. Is it possible to add another backing device without loosing the files already on the bcache device?
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Using dm-cache for transparent ongoing backup

Is there any chance to use dm-cache for ongoing SSD backup? I want to have very fast and cheap eventually consistent failure resistant partition. Use case: We have regular ssd (1Gb) (cache) + hdd (...
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Installing bcache on debian9

I am installing bcache tools on my debian-9 machine root@machine# uname -a Linux singlefs-ssd-vm 4.9.0-3-amd64 #1 SMP Debian 4.9.30-2+deb9u3 (2017-08-06) x86_64 GNU/Linux Commands tried: make-...
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Bcache writeback_percent max value

I'm tryng to set writeback_percent at a value > 40 but it only accept value between 0 and 40. If i set echo 50 > /sys/block/bcache0/bcache/writeback_percent then when i read the value more ...
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Getting files off bcache disk from different computer

I have a disk with a btrfs filesystem on top of bcache that was used in an old installation I no longer have (unintentionally nuked). When I plug in the drive, /dev/bcache0 doesn't show up and I'm not ...
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862 views

Use SSD for caching files from HDD

I don't have a name for this so I'll present my special user case: I have an hybrid-laptop made of a tablet slate of only 32GB SSD and a 500GB HDD build into the USB keyboard-dock and I want to make ...
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Cannot attach cache device to backing device

I have an LVM and I wanted to use bcache to cache one of its LVs. (Yes, I know I could use lvmcache, but I was having issues booting and I gave up using it.) First, I used blocks to convert the LV ...
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684 views

Is bcache solution for my ssd use case? [closed]

I recently bought a 240 GB SSD to speed up my computer with 1 TB HDD. I dual boot Windows and Linux. I want to use my new SSD in the most effective way. Reading through many sites led me to conclusion ...
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1answer
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What is grinding my HDDs and how do I stop it?

Something is grinding my hard disks all the time (a few KBs every second) and I can't seem to figure out what. My configuration: 4 spinning platters (/dev/sd[cdef]) assembled into a raid5 array, ...
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Error while installing Bcache on centOS

I am trying to setup Bcache on my existing system(Its risky,but we are not worried about losing any data ) . So my make and make install works proper but when I run the command make-bcache i receive ...
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Which is the correct dm-cache version

I am trying to install dm-cache on my CentOS machine. Which dm-cache version should I use. I read on wikipedia as below: Another dm-cache project with similar goals was announced by Eric Van ...
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bcache not working as expected with ramdisk as cache device

I was trying out bcache but i don't have an SSD so wanted to use free memory as a substitute. As ramdisk is listed in /proc/devices as block device i assumed this would work OK but with below simple ...
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bcache: writeback strategy

I'm using bcache with about 1 TByte of SSD caching for about 40 TByte of data. With writeback and 10% configured for bcache, about 100 GByte of dirty data exist only on the caching devices. I like ...
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Can I convert and deconvert a bache0 device to a standard block device and still read the filesystem?

When I set my raid (ex. /dev/md0) as a backing device. To work with the raid device, I have to interface with /dev/bcache0. However, if I wanted to add to the raid using mdadm, I need to address /...
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How to remove bcache0 volume?

I've tried echoing to detach and stop. The device will remove itself, but will show up again on reboot. One time on reboot, it restored the mdadm raid I had as a backing device! The other time I ...
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863 views

SSHD drive caching algorithm vs bcache/LVM

I read somewhere that the algorithms used by LVM/bcache are much better than the algorithms implemented by the H-HDD/SSHD drives. Is it true?
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Using the SSD area of a H-HDD drive with LVM/bcache

I heard that LVM/bcache can be used in Linux to store the most accessed files if there is a separate SSD drive. With a hybrid drive (SSHD/H-HDD), can the flash area be manually used by LVM/bcache as ...
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How to install bcache on Linux 4.1?

The official user documentation doesn't bother to say a word about how bcache is structured and how it can be installed. There's no .ko file in the source root after building with make. I speculate it'...
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How to restart a 'stopped' bcache device?

I need to upgrade some drive firmware and I'd like to shut down bcache for the duration. The docs show how to stop a bcache device: stop Write to this file to shut down the bcache device and ...
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622 views

Change Linux Bcache device type

I have accidentally configured my SSD as a backing device instead of a caching device. Simply trying either one of the following: sudo make-bcache -C /dev/sdb1 sudo make-bcache -C /dev/sdb Gives the ...
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Optimizing bcache

I have 3 HDD and 1 SSD, I have successfully mounted all drives to bcache. pavs@VAS:~$ df -h Filesystem Size Used Avail Use% Mounted on /dev/sda1 132G 35G 90G 28% / none 4....
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Using multiple SSDs as cache devices with bcache?

If we have three SSDs installed in a system, with a spare partition for the unused space on the SSD (/dev/sda2, /dev/sdb2 and /dev/sdc2). Can bcache be configured to use all three of those partitions ...
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bcache on md or md on bcache

bcache allows one or more fast disk drives such as flash-based solid state drives (SSDs) to act as a cache for one or more slower hard disk drives. If I understand correctly, an SSD* could be ...
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2k views

How to use an SSD for caching, so my hard disks can spin down?

I've got a file server with a bunch of disks running together in a BTRFS pool and want to add an SSD for caching. I'm not mainly after speeding up things, but want to catch the regular small accesses ...
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1answer
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How to regenerate initramfs so it can include bcache module?

Eventually I have converted root-fs into bcache (with the help of blocks). I skipped the step update-initramfs -u -k all because I've been using bcache on other partitions for some time, and I've ...
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How to remove cache device from bcache?

I believe, that once I made sure my cache device state is "clean": $ sudo cat /sys/block/bcache0/bcache/state I can just physically remove it from the machine when it is powered off or boot with ...
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SSD as a read cache for FREQUENTLY read data

I'm looking for ways to make use of an SSD to speed up my system. In “Linux equivalent to ReadyBoost?” (and the research that triggered for me) I've learned about bcache, dm-cache and EnhanceIO. All ...
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What exactly should we do to get bcache?

I am extremely confused about this bcache thingy here. On one hand some says that it's already incorporated into linux kernel. Then some says that I need to patch my linux kernel. If it's already ...
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BCache and disk encryption

I recently bought a new laptop with a 16Gb mSATA SSD cache drive. I haven't used that one yet. I have, however, opted for Ubuntu 13.04 with "Full Disk Encryption" for the main partition (is that what'...
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Where can I find a good tutorial for installing bcache? [closed]

Question is updated. Now bcache is part of the standard OS compilation. So it should be easy to install that now. I'll just order some SSD and some big HDD. Where can I found it? I found on the net ...