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 <sean_r_dur...@homedepot.com> > 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 <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.
