Quantum 3.5.1 User Manual

Event Handles for fsm.exe on a Windows Metadata Server

StorNext User’s Guide

335

Event Handles for fsm.exe on a Windows Metadata Server

The metadata server (FSM) has many data structures that are used 

internally. Each of the data structures has some locks 

(pthread_mutex_lock). Each lock is initialized as “uninitialized.” 
The first time the lock is used, a small amount of memory and an event 

(i.e., handle) are allocated. The memory and event/handle are retained 

by the system until the data structure is destroyed. Some locks that are 

part of structures are seldom used, and exist for rare conditions. If the 

lock is not used, the memory/event for that structure will never be 

allocated.
Some data structures are not destroyed during the life of the FSM. These 

include in-memory inodes and buffers and others.
When the system starts, handle use is minimal. After the FSM has been 

up for a while, the handle count increases as the inode and buffer cache 

are used. After a while, the system stabilizes at some number of handles. 

This occurs after all inodes and buffers have been used.
The maximum number of used handles can be reduced by shrinking the 

inode and/or buffer cache. However, changing these variables could 

significantly reduce system performance.

FSBlockSize, Metadata Disk Size, and JournalSize 
Settings

The FsBlockSize (FSB), metadata disk size, and JournalSize settings all 

work together. For example, the FsBlockSize must be set correctly in 

order for the metadata sizing to be correct. JournalSize is also dependent 

on the FsBlockSize. 
For FsBlockSize the optimal settings for both performance and space 

utilization are in the range of 16K or 64K. 
Settings greater than 64K are not recommended because performance 

will be adversely impacted due to inefficient metadata I/O operations.