See inline. > On May 21, 2020, at 10:13 AM, Kommu, Vinodh K. <vko...@dtcc.com> wrote: > > Thanks Eric for quick response. > > Yes, our VMs are equipped with NetBackup which is like file based backup and > it can restore any files or directories that were deleted from latest > available full backup. > > Can we create an empty collection with the same name which was deleted with > same number of shared & replicas and copy the content from restored core to > corresponding core?
Kind of. It is NOT necessary that it has the same name. There is no need at all (and I do NOT recommend) that you create the same number of replicas to start. As I said earlier, create a single-replica (i.e. leader-only) collection with the same number of shards. Copy _one_ data dir (not everything under core) to that _one_ corresponding replica. It doesn’t matter which replica you copy from > I mean, copy all contents (directories & files) under > Oldcollection_shard1_replica1 core from old collection to corresponding > Newcollection_shard1_replica1 core in new collection. Would this approach > will work? > As above, do not do this. Just copy the data dir from one of your backup copies to the leader-only replica. It doesn’t matter at all if the replica names are the same. The only thing that matters is that the shard number is identical. For instance, copy blah/blah/collection1_shard1_replica_57/data to blah/blah/collection1_shared1_replica_1/data if you want. Once you have a one-replica collection with the data in it and you’ve done a bit of verification, use ADDREPLICA to build it out. > Lastly anything needs to be aware in core.properties in newly created > collection or any reference pointing to new collection specific? Do not copy or touch core.properties, you can mess this up thoroughly by hand-editing. The _only_ thing you copy is the data directory, which will contain a tlog and index directory. And, the tlog isn’t even necessary. Best, Erick > > > Thanks & Regards, > Vinodh > > -----Original Message----- > From: Erick Erickson <erickerick...@gmail.com> > Sent: Thursday, May 21, 2020 6:17 PM > To: solr-user@lucene.apache.org > Subject: Re: How to restore deleted collection from filesystem > > ATTENTION: External Email – Be Suspicious of Attachments, Links and Requests > for Login Information. > > So what I’m reading here is that you have the _data_ saved somewhere, right? > By “data” I just mean the data directories under the replica. > > 1> Go ahead and recreate the collection. It _must_ have the same number of > shards. Make it leader-only, i.e. replicationFactor == 1 > 2> The collection will be empty, now shut down the Solr instances hosting any > of the replicas. > 3> Replace the data directory under each replica with the corresponding one > from the backup. “Corresponding” means from the same shard, which should be > obvious from the replica name. > 4> Start your Solr instances back up and verify it’s as you expect. > 5> Use ADDREPLICA to build out your collection to have as many replicas of > each shard as you require. NOTE: I’d do this gradually, maybe 2-3 at a time > then wait for them to become active before adding more. The point here is > that each ADDREPLICA will cause the entire index down from from the leader > and with that many documents you don’t want to saturate your network. > > Best, > Erick > >> On May 21, 2020, at 8:17 AM, Kommu, Vinodh K. <vko...@dtcc.com> wrote: >> >> Hi, >> >> One of our largest collection which holds 3.2 billion docs was deleted >> accidentally in QA environment. Unfortunately we don't have latest solr >> backup for this collection either to restore. The only option left for us is >> to restore deleted replica directories under data directory using netbackup >> restore process. >> >> We haven't done this way of restore before so following things are not clear: >> >> 1. As the collection was deleted (not created yet), if the necessary replica >> directories and files are restore to same location, will the collection >> works without creating it again? >> 2. If above option doesn't work, obviously we have to create collection but >> the replica names and placement may not be same as deleted collection's >> replica names and placements (creating collections using rule based >> replicas) so in this case what need to be done to restore the collection >> smoothly. Or is there any predefined steps available to handle this kind of >> scenario? Any suggestions is greatly appreciated. >> >> >> Thanks & Regards, >> Vinodh >> >> DTCC DISCLAIMER: This email and any files transmitted with it are >> confidential and intended solely for the use of the individual or entity to >> whom they are addressed. If you have received this email in error, please >> notify us immediately and delete the email and any attachments from your >> system. The recipient should check this email and any attachments for the >> presence of viruses. 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