[patch 0/8] WL4081 NDB Compressed LCP and Backup

[stewart]

This patch series creates two DB configuration options:
- CompressedLCP
- CompressedBackup

These can be enabled/disabled per ndbd node in the config file.

Any change is supported via rolling initial restart.

Enable/Disable Compressed BACKUP can be done online via the much-loved
DUMP interface.

You can do the same (via DUMP) for LCP, although if your config file
has compressed LCP *disabled* and you have a compressed LCP that is
attempted to be used during NR or SR, you'll get NF.

With compressed LCP *enabled* in the config, both compressed and
non-compressed LCPs can be read for NR or SR.

The following dumps are added:
- DUMP 13000
  Display current settings for CompressedBackup and CompressedLCP
- DUMP 13001 0
  Disable compressed backup
- DUMP 13001 1
  Enable compressed backup
- DUMP 13002 0
  Disable compressed LCP
- DUMP 13002 1
  Enable compressed LCP

Performance
-----------
Slight performance degredation at the moment. Investigating.

Compression
-----------
for 400MB of hugo table T1 data produced by hugoFill, i've gotten 50%
reduction in size written to disk

CPU Usage
---------
I've now clocked an ndbd at 150% CPU usage on ndb16 while doing
hugoFill and taking a backup.

Known Bugs
----------
- DirectIO on !XFS (at least)... failures on ndb16, not on my laptop.

Against...
----------
Patch series against 5.1-telco-6.2 although likely target for 6.3, not
6.2.
--
Stewart Smith