[OpenAFS] Does vos release/volume replication always initiates data transfer from RW site?

[Jeffrey Altman]

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On 8/5/2018 11:58 PM, Ximeng Guan wrote:
> Hello,
>
> We have one cell covering two sites. The WAN bandwidth between the two
> sites is relatively low, so we use volume replication to speed up the
> access.=20
>=20
> Those replicated volumes are often large in size. So replication to the=

> remote site is an operation whose cost cannot be neglected.
>=20
> Now with RW volumes at site A and their RO replication on servers at
> site B, we want to bring up a new file server at site B to balance the
> load. In other words we would like to =E2=80=9Coffload=E2=80=9D a major=
ity of the RO
> volumes from one server to a different server at Site B, without
> touching their RW masters at Site A.
>=20
>[...]>
> I wonder if there is a way to directly transfer those RO volumes btw
> servers at site B, without breaking the data integrity among the RO
> sites or affecting the atomicity of =E2=80=9Cvos release=E2=80=9D.

AuriStorFS supports the desired functionality including the ability to
copy and move readonly sites between file servers or vice partitions
attached to the same file server.

  https://www.auristor.com/openafs/migrate-to-auristor/

OpenAFS does not contain explicit functionality but it is possible using

  vos dump
  vos restore -id -readonly
  vos addsite -valid

to achieve similar results.  From the source server use "vos dump" to
generate a dump stream of the readonly volume you wish to replicate.
Pipe the output to "vos restore" specifying the destination server,
partition, the readonly volume id and the -readonly flag to specify the
volume type.  Finally, use "vos addsite" with the -valid flag to update
the location service entry for the volume.  The -valid flag indicates
that the readonly volume data is known to be present and consistent with
other sites.  Note that the -valid switch will not mark a site as "new"
if a "vos release" failed to update one or more sites.

Be careful to use publicly visible addresses when executing these command=
s.

Jeffrey Altman


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fn:Jeffrey Altman
n:Altman;Jeffrey
org:AuriStor, Inc.
adr:Suite 6B;;255 West 94Th Street;New York;New York;10025-6985;United St=
ates
email;internet:jaltman@auristor.com
title:Founder and CEO
tel;work:+1-212-769-9018
note;quoted-printable:LinkedIn: https://www.linkedin.com/in/jeffreyaltman=
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