Which Version

Which Version

[Jonathan Tripathy]

Hi Everyone,

Which version of bcache do I pull from git if I want the latest stable 
release? Am I correct in saying that the only way to obtain bcache is to 
pull and compile the entire Linux kernel from the bcache git server? 
Also, I wish to run bcache on my Xen Dom0, I'm guessing that these 
kernels have to correct Xen patches for this (As xen kernel patches are 
now mainline)?

Many Thanks

RE: Which Version

[James Harper]

> 
> Hi Everyone,
> 
> Which version of bcache do I pull from git if I want the latest stable release?
> Am I correct in saying that the only way to obtain bcache is to pull and
> compile the entire Linux kernel from the bcache git server?
> Also, I wish to run bcache on my Xen Dom0, I'm guessing that these kernels
> have to correct Xen patches for this (As xen kernel patches are now
> mainline)?
> 

I'm using the 3.2 branch, purely because I wanted to continue using the 3.2.x kernel from Debian. According to a question I asked recently it's mostly up to date. To do this, I checked out the 3.2 branch of bcache, and extracted a diff from the v3.2 tag (eg the mainstream linux), then applied this to the Debian source. I can't remember but I think the patch needed a bit of nudging in one place. I've only been testing for a few days but so far it's flawless.

When you create the bcache devices, I suggest setting the block size to 512 bytes, otherwise the resulting bcache devices have 4K sectors sizes and Xen doesn't like it. YMMV.

Because I'm layering lvm on bcache on md on sd, I had to tweak the initramfs scripts to make things load in the right order, and also you still need to put /boot on something grub understands eg /dev/sdX or /dev/mdX. Grub doesn't understand bcache (yet?).

James

RE: Which Version

[Jonathan Tripathy]

er if you believe you have received
this email in error.

On 14.08.2012 11:11, James Harper wrote:
>>
>> Hi Everyone,
>>
>> Which version of bcache do I pull from git if I want the latest 
>> stable release?
>> Am I correct in saying that the only way to obtain bcache is to pull 
>> and
>> compile the entire Linux kernel from the bcache git server?
>> Also, I wish to run bcache on my Xen Dom0, I'm guessing that these 
>> kernels
>> have to correct Xen patches for this (As xen kernel patches are now
>> mainline)?
>>
>
> I'm using the 3.2 branch, purely because I wanted to continue using
> the 3.2.x kernel from Debian. According to a question I asked 
> recently
> it's mostly up to date. To do this, I checked out the 3.2 branch of
> bcache, and extracted a diff from the v3.2 tag (eg the mainstream
> linux), then applied this to the Debian source. I can't remember but 
> I
> think the patch needed a bit of nudging in one place. I've only been
> testing for a few days but so far it's flawless.

Thanks for the info. Do you have the steps you used to do this? I've 
never patched a kernel before from another source....

I'd be using the Ubuntu kernel so the steps should be similar
>
> When you create the bcache devices, I suggest setting the block size
> to 512 bytes, otherwise the resulting bcache devices have 4K sectors
> sizes and Xen doesn't like it. YMMV.

Ah yes. I'm also using MD RAID. Does the chunk size matter at all?
>
> Because I'm layering lvm on bcache on md on sd, I had to tweak the
> initramfs scripts to make things load in the right order, and also 
> you
> still need to put /boot on something grub understands eg /dev/sdX or
> /dev/mdX. Grub doesn't understand bcache (yet?).

I'll be doing the same thing. What tweaks did you have to make? My 
bcache'ed MD RAID volume will be seperate to the boot and root 
partitions, so that shouldn't be an issue.

Thanks for your help

Re: Which Version

[Roy Sigurd Karlsbakk]

> Because I'm layering lvm on bcache on md on sd, I had to tweak the
> initramfs scripts to make things load in the right order, and also you
> still need to put /boot on something grub understands eg /dev/sdX or
> /dev/mdX. Grub doesn't understand bcache (yet?).

Why would you want bcache to understand your /boot partition? It's hardly in use anyway…

Vennlige hilsener / Best regards

roy
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