Re: [EXTERNAL] Re: Cassandra downgrade version
The real way to know for sure is for someone to go look at the sstable format changelog, and I’m traveling so it won’t be me, but for the record: If you snapshot everything, including system tables, you can always restore the snapshot - it’ll take downtime and you’ll lose data written after the snapshot, but that may be better than nothing -- Jeff Jirsa > On Apr 19, 2018, at 9:48 AM, Durity, Sean R > wrote: > > This answer surprises me, because I would expect NOT to be able to downgrade > if there are any changes in the sstable structure. I assume: > - Upgrade is done while the application is up and writing data (so > any new data is written in the new format) > - Any compactions that happen to run post-upgrade are written in the > new format > - A restore to the time just before upgrade would lose all new data > and would take time to move sstables back into place and restart all nodes – > requiring an outage. The data loss and outage time are usually unacceptable. > Therefore, I generally tell my development teams and change controls that a > backout is only a desperate, last-ditch effort. The upgrade goes forward > only. So, Lerh’s comment about testing in lower life cycles is critically > correct. > > So, the specific question here is whether there is any sstable format change > between 3.1.0 and 3.11.2. I don’t know if there is. > > > Sean Durity > > From: Lerh Chuan Low [mailto:l...@instaclustr.com] > Sent: Monday, April 16, 2018 6:52 PM > To: user@cassandra.apache.org > Subject: [EXTERNAL] Re: Cassandra downgrade version > > You should just be able to install 3.1.0 again if you need to as they are in > the 3.X line. To be really safe you can also take a snapshot and backup your > existing SSTables first..and always remember to test before upgrading in > Production :) > > On 17 April 2018 at 07:48, Abdul Patel wrote: > Hi All, > > I am.planning to upgrade my cassandra cluster from 3.1.0 to 3.11.2 . Just in > case if somethings goes back then do we have any rollback or downgrade option > in cassandra to older/ previous version? > > Thanks > > > > > The information in this Internet Email is confidential and may be legally > privileged. It is intended solely for the addressee. Access to this Email by > anyone else is unauthorized. If you are not the intended recipient, any > disclosure, copying, distribution or any action taken or omitted to be taken > in reliance on it, is prohibited and may be unlawful. When addressed to our > clients any opinions or advice contained in this Email are subject to the > terms and conditions expressed in any applicable governing The Home Depot > terms of business or client engagement letter. The Home Depot disclaims all > responsibility and liability for the accuracy and content of this attachment > and for any damages or losses arising from any inaccuracies, errors, viruses, > e.g., worms, trojan horses, etc., or other items of a destructive nature, > which may be contained in this attachment and shall not be liable for direct, > indirect, consequential or special damages in connection with this e-mail > message or its attachment.
Re: [EXTERNAL] Re: Cassandra downgrade version
On 04/19/2018 08:48 AM, Durity, Sean R wrote: > So, the specific question here is whether there is any sstable format > change between 3.1.0 and 3.11.2. I don’t know if there is. Here's how to quickly test that: git clone https://github.com/apache/cassandra.git cd cassandra/ git checkout cassandra-3.1 #(there was no 3.1.0 release) ant ./bin/cassandra ./tools/bin/cassandra-stress write n=1 ./bin/nodetool flush ls -l data/data/keyspace1/standard1-*/ pkill -f java git clean -xdf git checkout cassandra-3.11.2 # and repeat the above build, start, stress, ls https://paste.apache.org/I6dr -- Michael - To unsubscribe, e-mail: user-unsubscr...@cassandra.apache.org For additional commands, e-mail: user-h...@cassandra.apache.org
RE: [EXTERNAL] Re: Cassandra downgrade version
This answer surprises me, because I would expect NOT to be able to downgrade if there are any changes in the sstable structure. I assume: - Upgrade is done while the application is up and writing data (so any new data is written in the new format) - Any compactions that happen to run post-upgrade are written in the new format - A restore to the time just before upgrade would lose all new data and would take time to move sstables back into place and restart all nodes – requiring an outage. The data loss and outage time are usually unacceptable. Therefore, I generally tell my development teams and change controls that a backout is only a desperate, last-ditch effort. The upgrade goes forward only. So, Lerh’s comment about testing in lower life cycles is critically correct. So, the specific question here is whether there is any sstable format change between 3.1.0 and 3.11.2. I don’t know if there is. Sean Durity From: Lerh Chuan Low [mailto:l...@instaclustr.com] Sent: Monday, April 16, 2018 6:52 PM To: user@cassandra.apache.org Subject: [EXTERNAL] Re: Cassandra downgrade version You should just be able to install 3.1.0 again if you need to as they are in the 3.X line. To be really safe you can also take a snapshot and backup your existing SSTables first..and always remember to test before upgrading in Production :) On 17 April 2018 at 07:48, Abdul Patel mailto:abd786...@gmail.com>> wrote: Hi All, I am.planning to upgrade my cassandra cluster from 3.1.0 to 3.11.2 . Just in case if somethings goes back then do we have any rollback or downgrade option in cassandra to older/ previous version? Thanks The information in this Internet Email is confidential and may be legally privileged. It is intended solely for the addressee. Access to this Email by anyone else is unauthorized. If you are not the intended recipient, any disclosure, copying, distribution or any action taken or omitted to be taken in reliance on it, is prohibited and may be unlawful. When addressed to our clients any opinions or advice contained in this Email are subject to the terms and conditions expressed in any applicable governing The Home Depot terms of business or client engagement letter. The Home Depot disclaims all responsibility and liability for the accuracy and content of this attachment and for any damages or losses arising from any inaccuracies, errors, viruses, e.g., worms, trojan horses, etc., or other items of a destructive nature, which may be contained in this attachment and shall not be liable for direct, indirect, consequential or special damages in connection with this e-mail message or its attachment.
