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Pivotal Greenplum Command Center shows empty page for storage monitoring

Environment

Product Version
Pivotal Greenplum (GPDB) 4.3.x, 4.2.x
Pivotal Greenplum Command Center (GPCC) 1.x
EMC Data Computing Appliance  2.0.4.0

Symptom

After DCA upgrade to v2040, the Pivotal Greenplum Command Center shows an empty page for storage monitoring.

Cause

The Command Center uses gpsmon to track the real hostname and the GPDB catalog table to check segment configuration. Once the real hostname changes, there is an inconsistency between these two sources. GPCC would run a query like the one listed below to check space usage : 

select
max(sample_time) as sample_time,
count(distinct(hostname)) as hosts_current,
hosttype as hostname,
oid ,
SUM(total_bytes) as total_bytes,
sum(bytes_used) as bytes_used,
sum(bytes_available) as bytes_available
from
(select sample_time, hostname, filesystem, hosttype, oid,
round((total_bytes::real/1073741824)::numeric, 2) as total_bytes, round((bytes_used::real/1073741824)::numeric, 2) as bytes_used,
round((bytes_available::real/1073741824)::numeric, 2) as bytes_available
from
(select ctime as sample_time, * from diskspace_history
where ctime in (select distinct max(ctime) from diskspace_history )) a,
gpcmdr_instance_4340gpcc.fsmapcache,
(select distinct(hostname) as customerhostname,
case content when -1 then 'master' else 'sdw' end as hosttype from gp_segment_configuration group by hostname, content) gseg
where
mount = filesystem
and hostname = customerhostname
and hostname=host
and hosttype in ('master', 'sdw')) as c
group by hosttype, oid;

 This query will read the hostname from three tables:

  • diskspace_history
  • <gpcc_schema>.fsmapcache
  • gp_segment_configuration

Resolution

  • Manually change the hostname of each server to the same hostname in the gp_segment_configuration table (update /etc/sysconfig/network file with root account).
  • Then truncate diskspace_history table in gpperfmon db.
  • Finally, restart the database to ensure that gpsmon reads the correct hostname value.

Comments

  • Avatar
    Mike Berendsen

    In some circumstances it requires changing the hostname field in gp_segment_configuration to match the hostname reported by linux if hostname field in gp_segment_configuration is incorrect.

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