DB2 database is on storage. we are using 9.7 Storage administrators reported that today database was doing 5000 IOPS (during past days average number was 300 IOPS). Those are disk operations from server to disk system. db2data is currently on 89%. Today we did not do any large upload. How is this possible what happned to cause this problem?

In db2diag log only one ERROR is seen today:
2014-02-21-12.07.26.669877+060 E91992479E1392 LEVEL: Error
PID : 22867 TID : 1084623168 PROC : db2acd 0
INSTANCE: ctginst1 NODE : 000
FUNCTION: DB2 UDB, Health Monitor, HealthIndicator::update, probe:500
MESSAGE : ADM10500E Health indicator "Database Automatic Storage Utilization"
("db.auto_storage_util") breached the "upper" alarm threshold of "90
%" with value "94 %" on "database" "ctginst1.MAXDB71 ". Calculation:
"((db.auto_storage_used/db.auto_storage_total)*100);" =
"((30921187328 / 32821358592) * 100)" = "94 %". History (Timestamp,
Value, Formula): " (02/21/2014 11:57:26.209607, 89, ((29312966656 /
32821358592) * 100)), (02/21/2014 11:47:26.676942, 89, ((29311541248
/ 32821358592) * 100)), (02/21/2014 11:37:26.426393, 89,
((29324247040 / 32821358592) * 100)), (02/21/2014 11:27:26.984178, 90,
((29492969472 / 32821358592) * 100)), (02/21/2014 11:17:26.520087, 90,
((29499133952 / 32821358592) * 100)), (02/21/2014 11:07:26.945333, 93,
((30552121344 / 32821358592) * 100)), (02/21/2014 10:57:26.657101, 92,
((30317146112 / 32821358592) * 100)), (02/21/2014 10:47:26.264625, 92,
((30147538944 / 32821358592) * 100)), (02/21/2014 10:37:26.876803, 91,
((29968994304 / 32821358592) * 100))"

Any help is welcome. How to determine what happened? should we restart database to solve this?