[Gluster-devel] Need help with bitrot

Ajil Abraham ajil95.abraham at gmail.com
Thu Feb 25 15:28:35 UTC 2016

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
>> _______________________________________________
>> Gluster-devel mailing list
>> Gluster-devel at gluster.org
>> http://www.gluster.org/mailman/listinfo/gluster-devel
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