ZABBIX CERTIFIED SPECIALIST EXAM 3 2026/2027 | 150
Questions | Grade A | Pass Guaranteed - A+ Graded
SECTION 1: Zabbix Server Configuration & Tuning (Q1-Q18)
Q1: A Zabbix server is experiencing delayed data processing during peak hours. The
administrator notices that the HistoryCacheSize parameter is set to the default
16M. What is the most appropriate tuning action to improve history data write
performance?
A. Increase StartDiscoverers to handle more network discovery tasks
B. Increase HistoryCacheSize to 64M or higher to buffer more history values before
database writes
C. Decrease HousekeepingFrequency to clean data more aggressively
D. Increase StartTrappers to accept more incoming trapper connections
Correct Answer: B
Rationale: HistoryCacheSize controls the in-memory cache for history values before
they are flushed to the database. A larger cache reduces database write pressure and
improves throughput during peak loads. Option A affects discovery, not history
processing. Option C increases housekeeping overhead. Option D handles incoming
connections but not write buffering.
Q2: In zabbix_server.conf, which parameter controls the number of pre-forked
instances that handle active agent checks and active proxy connections?
A. StartPollers
B. StartTrappers
C. StartDBSyncers
D. StartPingers
Correct Answer: B
Rationale: StartTrappers defines the number of processes that handle incoming
connections from active agents and active proxies. StartPollers handles passive
,checks (SNMP, IPMI, agent passive). StartDBSyncers manages database
synchronization. StartPingers handles ICMP ping checks only.
Q3: An administrator needs to enable debug-level logging for only the discovery
component to troubleshoot network discovery issues without affecting overall server
performance. Which configuration approach is correct?
A. Set DebugLevel=5 in zabbix_server.conf and restart the server
B. Use the zabbix_server -R log_level_increase="discoverer" runtime
command
C. Modify zabbix_agentd.conf to increase the agent debug level
D. Set LogLevel=debug in the frontend under Administration → General
Correct Answer: B
Rationale: Zabbix supports runtime log level adjustments per process type using
log_level_increase and log_level_decrease without requiring a restart. Option
A would enable debug logging for all components, severely impacting performance.
Option C affects only the agent. Option D is not a valid frontend setting.
Q4: A Zabbix server monitoring 10,000 devices via passive agents is experiencing poller
congestion. The zabbix_server.log shows "Zabbix poller processes more than 75%
busy" repeatedly. Which parameter should be tuned first?
A. StartTrappers
B. StartPollers
C. CacheSize
D. HousekeepingFrequency
Correct Answer: B
Rationale: StartPollers directly controls the number of processes that execute
passive checks (agent, SNMP, IPMI). When pollers are consistently busy, increasing this
parameter distributes the check load. StartTrappers handles active checks.
CacheSize affects configuration cache, not polling throughput.
HousekeepingFrequency affects data cleanup.
,Q5: The Zabbix server configuration cache is consuming excessive memory and the
administrator wants to limit the maximum size. Which parameter in
zabbix_server.conf controls the configuration cache size?
A. CacheSize
B. ValueCacheSize
C. HistoryCacheSize
D. TrendCacheSize
Correct Answer: A
Rationale: CacheSize specifies the size of the configuration cache, which stores host,
item, and trigger configurations in memory. ValueCacheSize caches the latest item
values for trigger evaluation. HistoryCacheSize buffers history data before database
writes. TrendCacheSize caches trend data.
Q6: An organization is implementing Zabbix and needs to ensure that external scripts
executed by the server do not hang indefinitely. Which parameter should be configured
to enforce a maximum execution time for external checks, user parameters, and
system.run items?
A. Timeout
B. TrapperTimeout
C. UnreachableTimeout
D. ScriptTimeout
Correct Answer: A
Rationale: The Timeout parameter in zabbix_server.conf defines the maximum
execution time (in seconds) for external checks, user parameters, system.run items, and
scripts executed by the server. TrapperTimeout does not exist.
UnreachableTimeout controls how long to wait before marking a host unreachable.
ScriptTimeout is not a valid Zabbix server parameter.
Q7: A Zabbix administrator notices that trend data calculations are causing frequent
database reads. To reduce this I/O overhead, which cache parameter should be
increased?
A. HistoryCacheSize
B. TrendCacheSize
, C. ValueCacheSize
D. CacheSize
Correct Answer: B
Rationale: TrendCacheSize controls the in-memory cache for trend data (hourly
aggregated statistics). Increasing it reduces database reads when triggers or functions
reference trend data. HistoryCacheSize buffers raw history values.
ValueCacheSize caches the latest values. CacheSize stores configuration data.
Q8: During a performance audit, an administrator discovers that the Zabbix server is
spawning too many database synchronization processes, causing database connection
pool exhaustion. Which parameter directly controls the number of database syncer
processes?
A. StartPollers
B. StartDBSyncers
C. StartPingers
D. StartTrappers
Correct Answer: B
Rationale: StartDBSyncers defines the number of processes that flush data from the
history cache to the database. Too many syncers can overwhelm the database
connection pool. StartPollers executes checks. StartPingers handles ICMP.
StartTrappers handles active connections.
Q9: A Zabbix server is configured with StartDiscoverers=5 and network discovery
is running slowly. The administrator increases this to StartDiscoverers=20. What is
a potential negative consequence of this change?
A. Active agent checks will be rejected due to trapper process exhaustion
B. Increased network traffic and target device load from parallel discovery probes
C. Database syncer processes will automatically decrease
D. Trend cache will be flushed more frequently
Correct Answer: B
Rationale: More discoverers means more parallel discovery processes sending probes
(ICMP, SNMP, Zabbix agent) to target networks, which increases network bandwidth
Questions | Grade A | Pass Guaranteed - A+ Graded
SECTION 1: Zabbix Server Configuration & Tuning (Q1-Q18)
Q1: A Zabbix server is experiencing delayed data processing during peak hours. The
administrator notices that the HistoryCacheSize parameter is set to the default
16M. What is the most appropriate tuning action to improve history data write
performance?
A. Increase StartDiscoverers to handle more network discovery tasks
B. Increase HistoryCacheSize to 64M or higher to buffer more history values before
database writes
C. Decrease HousekeepingFrequency to clean data more aggressively
D. Increase StartTrappers to accept more incoming trapper connections
Correct Answer: B
Rationale: HistoryCacheSize controls the in-memory cache for history values before
they are flushed to the database. A larger cache reduces database write pressure and
improves throughput during peak loads. Option A affects discovery, not history
processing. Option C increases housekeeping overhead. Option D handles incoming
connections but not write buffering.
Q2: In zabbix_server.conf, which parameter controls the number of pre-forked
instances that handle active agent checks and active proxy connections?
A. StartPollers
B. StartTrappers
C. StartDBSyncers
D. StartPingers
Correct Answer: B
Rationale: StartTrappers defines the number of processes that handle incoming
connections from active agents and active proxies. StartPollers handles passive
,checks (SNMP, IPMI, agent passive). StartDBSyncers manages database
synchronization. StartPingers handles ICMP ping checks only.
Q3: An administrator needs to enable debug-level logging for only the discovery
component to troubleshoot network discovery issues without affecting overall server
performance. Which configuration approach is correct?
A. Set DebugLevel=5 in zabbix_server.conf and restart the server
B. Use the zabbix_server -R log_level_increase="discoverer" runtime
command
C. Modify zabbix_agentd.conf to increase the agent debug level
D. Set LogLevel=debug in the frontend under Administration → General
Correct Answer: B
Rationale: Zabbix supports runtime log level adjustments per process type using
log_level_increase and log_level_decrease without requiring a restart. Option
A would enable debug logging for all components, severely impacting performance.
Option C affects only the agent. Option D is not a valid frontend setting.
Q4: A Zabbix server monitoring 10,000 devices via passive agents is experiencing poller
congestion. The zabbix_server.log shows "Zabbix poller processes more than 75%
busy" repeatedly. Which parameter should be tuned first?
A. StartTrappers
B. StartPollers
C. CacheSize
D. HousekeepingFrequency
Correct Answer: B
Rationale: StartPollers directly controls the number of processes that execute
passive checks (agent, SNMP, IPMI). When pollers are consistently busy, increasing this
parameter distributes the check load. StartTrappers handles active checks.
CacheSize affects configuration cache, not polling throughput.
HousekeepingFrequency affects data cleanup.
,Q5: The Zabbix server configuration cache is consuming excessive memory and the
administrator wants to limit the maximum size. Which parameter in
zabbix_server.conf controls the configuration cache size?
A. CacheSize
B. ValueCacheSize
C. HistoryCacheSize
D. TrendCacheSize
Correct Answer: A
Rationale: CacheSize specifies the size of the configuration cache, which stores host,
item, and trigger configurations in memory. ValueCacheSize caches the latest item
values for trigger evaluation. HistoryCacheSize buffers history data before database
writes. TrendCacheSize caches trend data.
Q6: An organization is implementing Zabbix and needs to ensure that external scripts
executed by the server do not hang indefinitely. Which parameter should be configured
to enforce a maximum execution time for external checks, user parameters, and
system.run items?
A. Timeout
B. TrapperTimeout
C. UnreachableTimeout
D. ScriptTimeout
Correct Answer: A
Rationale: The Timeout parameter in zabbix_server.conf defines the maximum
execution time (in seconds) for external checks, user parameters, system.run items, and
scripts executed by the server. TrapperTimeout does not exist.
UnreachableTimeout controls how long to wait before marking a host unreachable.
ScriptTimeout is not a valid Zabbix server parameter.
Q7: A Zabbix administrator notices that trend data calculations are causing frequent
database reads. To reduce this I/O overhead, which cache parameter should be
increased?
A. HistoryCacheSize
B. TrendCacheSize
, C. ValueCacheSize
D. CacheSize
Correct Answer: B
Rationale: TrendCacheSize controls the in-memory cache for trend data (hourly
aggregated statistics). Increasing it reduces database reads when triggers or functions
reference trend data. HistoryCacheSize buffers raw history values.
ValueCacheSize caches the latest values. CacheSize stores configuration data.
Q8: During a performance audit, an administrator discovers that the Zabbix server is
spawning too many database synchronization processes, causing database connection
pool exhaustion. Which parameter directly controls the number of database syncer
processes?
A. StartPollers
B. StartDBSyncers
C. StartPingers
D. StartTrappers
Correct Answer: B
Rationale: StartDBSyncers defines the number of processes that flush data from the
history cache to the database. Too many syncers can overwhelm the database
connection pool. StartPollers executes checks. StartPingers handles ICMP.
StartTrappers handles active connections.
Q9: A Zabbix server is configured with StartDiscoverers=5 and network discovery
is running slowly. The administrator increases this to StartDiscoverers=20. What is
a potential negative consequence of this change?
A. Active agent checks will be rejected due to trapper process exhaustion
B. Increased network traffic and target device load from parallel discovery probes
C. Database syncer processes will automatically decrease
D. Trend cache will be flushed more frequently
Correct Answer: B
Rationale: More discoverers means more parallel discovery processes sending probes
(ICMP, SNMP, Zabbix agent) to target networks, which increases network bandwidth
