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Questions tagged [bcache]

Bcache is a Linux block layer cache that uses SSDs to cache other block devices.

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BCache + MDADM running extremely slow

I have 3x 14TB toshiba drives MDAdmin (/dev/md0) raid 5'd together that are setup as a bcache back. I have a 256GB fast SSD as the front of the bache. writeback is enabled. After a few days, the ...
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how to release device locked by bcache

Today I bought a 128MB SSD disk, installed it, then installed bcache-tools. After attempting to access the device I got these errors: root@dev:/sys/block/sda/bcache# make-bcache -B /dev/sdb1 /dev/...
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bcache performance degradation on newer version of Ubuntu kernel

I have an elasticsearch cluster which uses Azure storage with a local SSD bcache. One of the machines has poorer performance because it has cache misses while the other two machines never have cache ...
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332 views

Can I use bcache without losing any data first?

My Ubuntu 17.04 (64 bit) box has: 1 x SSD (used for the OS) 2 x HDD (used for data, such as /home and backups etc.) 8GB RAM If I shrink my SSD and create an empty partition for caching my HDD(s), is ...
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73 views

How to find block number from struct bio?

I want to use SSD as cache for block as part of my project based on VM. So I want to find the block number from read request. How to find block number of hard disk for a read/ write requests in Linux ...
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1answer
270 views

Got a new SSD, don't want to wear it out but I still want to use some of it to store data files together with the old HDD

I've bought a brand new 250GB Samsung 850 EVO for my laptop, that I want to use as primary storage device, together with the old - but still pretty functioning - 250GB 7500 RPM HDD that I put in the ...
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2answers
4k views

How to install Ubuntu with both disk encryption AND SSD caching

I'm using Ubuntu in a corporate environment, and our security policy states that we have to use full disk encryption. I've also got a laptop with a 32GB mSATA SSD and 750GB of spinning rust. My ...
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3answers
1k views

Does bcache support use of an LVM logical volume as a cache device?

I've got a 64GB SSD and a 3TB hard drive in my system running Ubuntu 14.04. The SSD has a small root partition with rest of the device allocated to an LVM physical volume. From that LVM physical ...
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1answer
3k views

What happens in bcache if the cache ssd dies?

I'm creating a NAS and I've been doing a lot of research on the different SSD caches. I have a 120gb ssd which is more than enough for the OS so I want to use most of it as a cache for the md raid5 ...
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1answer
495 views

Recovering disk with corrupted superblock

I am trying to recover a disk that has corrupted superblock but I cant seem to unmount the disk at all. I used bcache for the three extra drive after a reboot one of the drive stopped working. so I ...
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3answers
12k views

How to setup bcache?

I've tried to set up bcache in Ubuntu 14.04 with a fresh install and an empty /home partition (/dev/sdb2) as a backing device. I have a running system on my SSD and I'd like to use its /dev/sda2 ...
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402 views

bcache is not caching all drives

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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1answer
1k views

error in bcache

I used bcache to cache my 24GB SSD using this tutorial. I tried to back up my HDD with: sudo make-bcache -B /dev/sdb1 But I get this error: Can't open dev /dev/sdb1: Device or resource busy My ...
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0answers
412 views

Bcache hangs on Ubuntu 14.04

I successfully setup my system to use bache in /home partition (200GB SSD partition as cache for 500 GB HDD partition). However, I keep receiving these messages: INFO: task bcache_writebac:222 ...
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1answer
187 views

If I convert my Ubuntu into Xen hypervizor, will I lose access to the bcache devices?

I'd like to test Xen a little. For obvious reasons I cannot do it under VirtualBox (or can I?) As I understand, Xen works by changing the kernel, thus possibly interfering with the custom kernel ...
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1answer
8k views

“Device not found or ignored” when creating physical volume with bcache

I'm attempting to create an LVM volume on a bcache device, but getting "device not found or recognized", despite lsblk clearly showing the device, and bcache state showing "clean". OS is Ubuntu 13.10 ...
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1answer
407 views

compressed block device

I wanted to experiment with combining bcache and a compressed block device on a hdd and seeing if this will speedup the boot time. Are there any means of compressing a block device at the block level? ...
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2answers
1k views

Using btrfs with bcache on /

I am using btrfs with bcache for / on Ubuntu 13.10. It's fast. Unfortunately, during normal boots the step "Scanning for btrfs filesystems" fails. To successfully boot I have to enter recovery mode ...
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1answer
1k views

Reccomended options for mounting /dev/bcache0 as /home

I have set up /dev/sda3 on my SSD to cache /dev/sdb3 on my HDD as /dev/bcache0 using bcache in Ubuntu 13.10 (kernel 3.11.0-14-generic). I have formatted it as ext4. I currently mount / (on my SSD) ...
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1answer
126 views

Does using an extended cache improve performance?

Does using a extended cache (readyboost-like) improves the overall performance? I read a lot about it and some says that it's just for old machines with low RAM and also the 480mbit/s of usb2.0 was ...
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2answers
10k views

What are the advantages/disadvantages of different SSD to HDD cacheing options (dm-cache, flashcashe…)?

There appear to be various different technologies available to use an SSD to act as a cache for HHDs. The ones I know of: dm-cache (by Redhat - in the 3.9 Kernel, so it should be in ubuntu 13.10) ...
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4answers
35k views

How do I install and use flashcache/bcache to cache HDD to SSD?

I want to know if there is anyone who has tried installing and running their kernel built with flashcache or bcache for SSD caching? How did you manage to do it?
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3answers
4k views

Does bcache require a fresh installation?

Because my notebook has a SSD and a HDD, I want use the SSD as cache just like Rapid Storage in windows. I find bcache offers this functionality so I decide to try it. I got bcache and bcache-tools ...