Dear Lorina,
Thank you very much for your answer and to your support team.
I understand why you won't document the special case RF = N = 3. Thank
you for clarifying this special case.
I've found this answer from Marcus Eriksson stating that autocompaction
should be reenabled after the migration:
https://www.mail-archive.com/user@cassandra.apache.org/msg40305.html
It would be nice to add this step in the documentation if it's not
automatic after the cassandra restart.
What about what Stefano was asking? (thanks by the way, Stefano!)
Can anyone confirm the recent versions of Cassandra (from which version)
do not require anything specific but the -inc switch when migrating to
incremental repair?
I can understand the migration procedure is not mandatory, especially
when there is not much data to migrate, but the documentation seems to
imply that if the migration steps are not done, the first incremental
repair could take a very long time.
Can anyone clarify this point please?
Did anyone try incremental repairs without the migration procedure with
a sensible amount of data to migrate?
How much longer did it take?
Thank you very much for your help
Kind regards
Reynald
On 19/11/2015 22:43, Lorina Poland wrote:
Hi Reynald,
I asked Support about your email. They said that since your RF = N (3
nodes, 3 replicates), one full repair on any node will suffice. You
are an edge case, so we won't be documenting this solution.
As for your other questions, I'm guessing you are not a DataStax
customer. I would recommend the Apache Cassandra user forum
(http://www.mail-archive.com/user@cassandra.apache.org/), where you
can ask your questions and receive feedback. Stackoverflow is another
good forum for Cassandra questions
(http://stackoverflow.com/questions/tagged/cassandra).
Sincerely,
Lorina Poland
datastax_logo.png <http://www.datastax.com/>
LORINA POLAND
Senior Technical Writer | lor...@datastax.com <mailto:lor...@datastax.com>
linkedin.png <https://www.linkedin.com/in/lorinapoland>twitter.png
<https://twitter.com/datastax>
<http://cassandrasummit-datastax.com/?utm_campaign=summit15&utm_medium=summiticon&utm_source=emailsignature>
On Thu, Nov 19, 2015 at 3:13 AM, Stefano Ortolani <ostef...@gmail.com
<mailto:ostef...@gmail.com>> wrote:
As far as I know, docs is quite inconsistent on the matter.
Based on some research here and on IRC, recent versions of
Cassandra do no require anything specific when migrating to
incremental repairs but the the -inc switch even on LCS.
Any confirmation on the matter is more than welcome.
Regards,
Stefano
On Wed, Nov 18, 2015 at 3:59 PM, Reynald Bourtembourg
<reynald.bourtembo...@esrf.fr
<mailto:reynald.bourtembo...@esrf.fr>> wrote:
Well, By re-reading my e-mail, I understood the rationale
behind doing a full sequential repair for each node. I was
confused by the fact that in our case, we have 3 nodes with RF
= 3, so all the nodes are storing all replicas. So we are in a
special case. As soon as you have more than 3 nodes, this is
no longer the case. In any case, in our special case (3 nodes
and RF=3), could we apply the following migration procedure?:-
disableautocompaction on all nodes at the same time - run the
full sequential repair - For each node: - stop the
node - Use the tool sstablerepairedset to mark all the
SSTables that were created before you disabled compaction.
- Restart Cassandra I'd be glad if someone could answer to
my other questions in any case ;-). Thanks in advance for your
helpReynald
On 18/11/2015 16:45, Reynald Bourtembourg wrote:
Hi, We currently have a 3 nodes Cassandra cluster with RF =
3. We are using Cassandra 2.1.7. We would like to start using
incremental repairs. We have some tables using LCS compaction
strategy and some others using STCS. Here is the procedure
written in the documentation:
To migrate to incremental repair, one node at a time:
1. Disable compaction on the node using nodetool
disableautocompaction.
2. Run the default full, sequential repair.
3. Stop the node.
4. Use the tool sstablerepairedset to mark all the SSTables
that were created before you disabled compaction.
5. Restart cassandra
In our case, a full sequential repair takes about 5 days. If
I follow the procedure described above and if my
understanding is correct, it's gonna take at least 15 days (3
repairs of 5 days) before to be able to use the incremental
repairs, right(?), since we need to do it one node at a time
(one full sequential repair per node?). If my understanding
is correct, what is the rationale behind the fact that we
need to run a full sequential repair once for each node? I
understood a full sequential repair would repair all the
sstables on all the nodes. So doing it only once should be
enough, right? Is it possible to do the following instead of
what is written in the documentation?: -
disableautocompaction on all nodes at the same time - run
the full sequential repair - For each node: - stop
one node - Use the tool sstablerepairedset to mark
all the SSTables that were created before you disabled
compaction. - Restart Cassandra Without having to run
the full sequential repair 3 times? The documentation states
that if we don't execute this migration procedure, the first
time we will run incremental repair, Cassandra will perform
size-tiering on all SSTables because the repair/unrepaired
status is unknown and this operation can take a long time. Do
you think this operation could take more than 15 days in our
case? I understood that we only need to use
sstablerepairedset on the SSTables related to the tables
using LCS compaction strategy and which were created before
the auto compaction was disabled. Is my understanding
correct? The documentation is not very explicit but I suppose
the following sentence: "4. Use the tool sstablerepairedset
to mark all the SSTables that were created before you
disabled compaction." means we need to invoke
"sstablerepairedset --is-repaired -f
list_of_sstable_names.txt" on the LCS SSTables that were
created before the compaction was disabled. Is this correct?
Do we need to enableautocompaction again after the Cassandra
restart or is it done automatically? Would you recommend us
to upgrade our Cassandra version before starting the
incremental repair migration? Thank you for your help and
sorry for the long e-mail. Reynald
