Disk space threshold notification

You can use the hwDiskFull event type (defined in the default event rules Disk80PercentFull and Disk90PercentFull) to receive notifications when any one of the system’s SPUs’ disk space becomes more than 80-85, or 90-95 percent full.

Configuring disk space threshold

If you are on Netezza Performance Server 11.2.1.4 or later, you can configure disk space threshold by using the sysmgr.spuDatasliceUsageThresholds system registry variable.

Example:

[nz@recovers1 ~]$ nzsystem showRegistry | grep -i spuDatasliceUsageThresholds
sysmgr.spuDatasliceUsageThresholds = 90

With the setting set up, you receive notifications when any one of the disk's space utilization becomes more than 90%.

Syntax

The following is the syntax for the event rule Disk80PercentFull:

-name Disk80PercentFull -on no -eventType hwDiskFull -eventArgsExpr 
'$threshold == 80 || $threshold == 85' -notifyType email -dst 
'you@company.com' -ccDst '' -msg 'NPS system $HOST - $hwType $hwId 
$partition partition is $value % full at $eventTimestamp.' -bodyText 
'$notifyMsg\n\nSPA ID: $spaId\nSPA Slot: $spaSlot\nThreshold: 
$threshold\nValue: $value\n' -eventAggrCount 50

The following is the syntax for the event rule Disk90PercentFull:

-name Disk90PercentFull -on no -eventType hwDiskFull -eventArgsExpr 
'$threshold == 90 || $threshold == 95' -notifyType email -dst '<your 
email here>' -ccDst '' -msg 'URGENT: NPS system $HOST - $hwType $hwId 
$partition partition is $value % full at $eventTimestamp.' -bodyText 
'$notifyMsg\n\nSPA ID: $spaId\nSPA Slot: $spaSlot\nThreshold: 
$threshold\nValue: $value\n'c -eventAggrCount 50

The following table lists the arguments to the DiskSpace event rules.

Table 1. DiskSpace event rules
Arguments	Description	Example
hwType	The type of hardware affected	spu, disk
hwId	The hardware ID of the disk that has the disk space issue	1013
spaId	The ID of the SPA
spaSlot	The SPA slot number
partition	The data slice number	0,1,2,3
threshold	The threshold value	75, 80, 85, 90, 95
value	The actual percentage full value	84

After you enable the event rule, the event manager sends you an email when the system disk space percentage exceeds the first threshold and is below the next threshold value. The event manager sends only one event per sampled value.

For example, if you enable the event rule Disk80PercentFull, which specifies thresholds 80 and 85 percent, the event manager sends you an email when the disk space is at least 80, but less than 85 percent full. When you receive the email, your actual disk space might be 84 percent full.

The event manager maintains thresholds for the values 75, 80, 85, 90, and 95. Each of these values (except for 75) can be in the following states:

Armed: The system has not reached this value.
Disarmed: The system has exceeded this value.
Fired: The system has reached this value.
Rearmed: The system has fallen below this value.

Note: If you enable an event rule after the system reached a threshold, you are not notified that it reached this threshold until you restart the system.

The following table lists these thresholds and their states.

Table 2. Threshold and states
Threshold	Armed	Triggered	Disarmed	Rearmed
75	never	never	never	never
80	startup	>= 80 && < 85	>= 80	< 75
85	startup	>= 85 && < 90	>= 85	< 80
90	startup	>= 90 && < 95	>= 90	< 85
95	startup	>= 95	>= 95	< 90

After the Netezza Performance Server System Manager sends an event for a particular threshold, it disarms all thresholds at or below that value. (So if 90 is triggered, it does not trigger again until it is rearmed). The Netezza Performance Server System Manager rearms all disarmed higher thresholds when the disk space percentage full value falls below the previous threshold, which can occur when you delete tables or databases. The Netezza Performance Server System Manager arms all thresholds (except 75) when the system starts up.

Tip: To ensure maximum coverage, enable both event rules Disk80PercentFull and Disk90PercentFull.

To send an email when the disk is more than 80 percent full, enable the predefined event rule Disk80PercentFull:

nzevent modify -u admin -pw password -name Disk80PercentFull -on 
yes -dst jdoe@company.com

If you receive a diskFull notification from one or two disks, your data might be unevenly distributed across the data slices (data skew). Data skew can adversely affect performance for the tables that are involved and for combined workloads.

Tip: Consider aggregating the email messages for this event. Set the aggregation count to the number of SPUs.