[Gluster-devel] Need help with bitrot

[Ajil Abraham]

Thanks Joseph for the precise set of information.  I will follow these.

- Ajil

On Fri, Feb 26, 2016 at 7:05 AM, Joseph Fernandes <josferna at redhat.com>
wrote:

> Hope this helps
>
> Courtesy : Raghvendra Talur (rtalur at redhat.com)
>
> 1. Clone glusterfs repo to your laptop and get acquainted with dev
> workflow.
> https://gluster.readthedocs.org/en/latest/Developer-guide/Developers-Index/
>
> 2. If you find using your laptop as the test machine for Gluster as too
> scary, here is a vagrant based mechanism to get VMs setup on your laptop
> easily for Gluster testing.
> http://comments.gmane.org/gmane.comp.file-systems.gluster.devel/13494
>
> 3.Find my Gluster Introduction blog post here in the preview link:
>
>
>
> https://6227134958232800133_bafac39c28bee4f256bbbef7510c9bb9b44fca05.blogspot.com/b/post-preview?token=s6_4MVIBAAA.zY--3ij00CkDwnitBOwnFBowEvCsKZ0o4ToQ0KYk9Po4pKujPj9ugmn-fm-XUFdLQxU50FmnCxBBr_IkSzuSlA.l_XFe1UvIEAiqkFAZZPdqQ&postId=4168074834715190149&type=POST
>
> 4. Follow all the lessons here in Translator 101 series for build on your
> understanding of Gluster.
>
> http://pl.atyp.us/hekafs.org/index.php/2011/11/translator-101-class-1-setting-the-stage/
>
> http://hekafs.org/index.php/2011/11/translator-101-lesson-2-init-fini-and-private-context
>
> http://hekafs.org/index.php/2011/11/translator-101-lesson-3-this-time-for-real
>
> http://hekafs.org/index.php/2011/11/translator-101-lesson-4-debugging-a-translator
>
>
> 5. Try to fix or understand any of the bugs in this list
>
> https://bugzilla.redhat.com/buglist.cgi?bug_status=NEW&bug_status=ASSIGNED&classification=Community&f1=keywords&list_id=4424622&o1=substring&product=GlusterFS&query_format=advanced&v1=easyfix
>
>
> Regards,
> Joe
>
>
> ----- Original Message -----
> From: "Ajil Abraham" <ajil95.abraham at gmail.com>
> To: "FNU Raghavendra Manjunath" <rabhat at redhat.com>
> Cc: "Gluster Devel" <gluster-devel at gluster.org>
> Sent: Thursday, February 25, 2016 8:58:35 PM
> Subject: Re: [Gluster-devel] Need help with bitrot
>
> Thanks FNU Raghavendra. Does the signing happen only when the file data
> changes or even when extended attribute changes?
>
> I am also trying to understand the Gluster internal data structures. Are
> there any materials for the same? Similarly for the translators, the way
> they are stacked on client & server side, how control flows between them.
> Can somebody please help?
>
> - Ajil
>
> On Thu, Feb 25, 2016 at 7:27 AM, FNU Raghavendra Manjunath <
> rabhat at redhat.com > wrote:
>
>
>
> Hi Ajil,
>
> Expiry policy tells the signer (Bit-rot Daemon) to wait for a specific
> period of time before signing a object.
>
> Whenever a object is modified, a notification is sent to the signer by
> brick process (bit-rot-stub xlator sitting in the I/O path) upon getting a
> release (i.e. when all the fds of that object are closed). The expiry
> policy tells the signer to wait for some time (by default its 120 seconds)
> before signing that object. It is done because, suppose the signer starts
> signing (i.e. read the object + calculate the checksum + store the
> checksum) a object the object gets modified again, then a new notification
> has to be sent and again signer has to sign the object by calculating the
> checksum. Whereas if the signer waits for some time and receives a new
> notification on the same object when its waiting, then it can avoid signing
> for the first notification.
>
> Venky, do you want to add anything more?
>
> Regards,
> Raghavendra
>
>
>
> On Wed, Feb 24, 2016 at 12:28 AM, Ajil Abraham < ajil95.abraham at gmail.com
> > wrote:
>
>
>
> Hi,
>
> I am a student interested in GlusterFS. Trying to understand the design of
> GlusterFS. Came across the Bitrot design document in Google. There is a
> mention of expiry policy used to sign the files. I did not clearly
> understand what the expiry policy is. Can somebody please help?
>
> -Ajil
>
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