[Gluster-devel] Need help with bitrot
ajil95.abraham at gmail.com
Fri Feb 26 01:13:47 UTC 2016
Thank you sir. I will read these documents.
On Thu, Feb 25, 2016 at 9:05 PM, FNU Raghavendra Manjunath <
rabhat at redhat.com> wrote:
> As of now, signing happens only upon data modification. Metadata changes
> and xattr changes does not trigger signing.
> For more information about gluster and its internals, you can look here "
> On Thu, Feb 25, 2016 at 10:28 AM, Ajil Abraham <ajil95.abraham at gmail.com>
>> 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?
>>> On Wed, Feb 24, 2016 at 12:28 AM, Ajil Abraham <ajil95.abraham at gmail.com
>>> > wrote:
>>>> 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?
>>>> Gluster-devel mailing list
>>>> Gluster-devel at gluster.org
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