When a Raft peer fails, YugabyteDB executes an automatic remote bootstrap to create a new peer from the remaining ones.

If a majority of Raft peers fail for a given tablet, you need to manually execute the equivalent of a remote bootstrap. A list of tablets is available via the yb-master-ip:7000/tablet-replication yb-admin UI.

Assume you have a cluster where the following applies:

  • Replication factor is 3.
  • A tablet with UUID TABLET1.
  • Three tablet peers, with one in good working order, referred to as NODE_GOOD, and two broken peers referred to as NODE_BAD1 and NODE_BAD2.
  • Some of the tablet-related data is to be copied from the good peer to each of the bad peers until the majority of them are restored.

These are the steps to follow:

  • On NODE_GOOD, create an archive of the WALS (Raft data), RocksDB (regular) directories, intents (transactions data), and snapshots directories for TABLET1.

  • Copy these archives over to NODE_BAD1, on the same drive that TABLET1 currently has its Raft and RocksDB data.

  • Stop NODE_BAD1, as the file system data underneath will change.

  • Remove the old WALS, RocksDB, intents, snapshots data for TABLET1 from NODE_BAD1.

  • Unpack the data copied from NODE_GOOD into the corresponding (now empty) directories on NODE_BAD1.

  • Restart NODE_BAD1 so it can bootstrap TABLET1 using this new data.

  • Restart NODE_GOOD so it can properly observe the changed state and data on NODE_BAD1.

At this point, NODE_BAD2 should be automatically fixed and removed from its quorum, as it has gotten a majority of healthy peers.

Note that typically, when you try to find tablet data, you would use a find command across the --fs_data_dir paths.

In the following example, assume that is set to /mnt/d0 and your tablet UUID is c08596d5820a4683a96893e092088c39:

find /mnt/d0/ -name '*c08596d5820a4683a96893e092088c39*'
/mnt/d0/yb-data/tserver/wals/table-2fa481734909462385e005ba23664537/tablet-c08596d5820a4683a96893e092088c39
/mnt/d0/yb-data/tserver/tablet-meta/c08596d5820a4683a96893e092088c39
/mnt/d0/yb-data/tserver/consensus-meta/c08596d5820a4683a96893e092088c39
/mnt/d0/yb-data/tserver/data/rocksdb/table-2fa481734909462385e005ba23664537/tablet-c08596d5820a4683a96893e092088c39
/mnt/d0/yb-data/tserver/data/rocksdb/table-2fa481734909462385e005ba23664537/tablet-c08596d5820a4683a96893e092088c39.intents
/mnt/d0/yb-data/tserver/data/rocksdb/table-2fa481734909462385e005ba23664537/tablet-c08596d5820a4683a96893e092088c39.snapshots

The data you would be interested is the following:

  • For the Raft WALS:

    /mnt/d0/yb-data/tserver/wals/table-2fa481734909462385e005ba23664537/tablet-c08596d5820a4683a96893e092088c39
    
  • For the RocksDB regular database:

    /mnt/d0/yb-data/tserver/data/rocksdb/table-2fa481734909462385e005ba23664537/tablet-c08596d5820a4683a96893e092088c39
    
  • For the intents files:

    /mnt/d0/yb-data/tserver/data/rocksdb/table-2fa481734909462385e005ba23664537/tablet-c08596d5820a4683a96893e092088c39.intents
    
  • For the snapshot files:

    /mnt/d0/yb-data/tserver/data/rocksdb/table-2fa481734909462385e005ba23664537/tablet-c08596d5820a4683a96893e092088c39.snapshots