Monitoring Chunk Servers

By monitoring chunk servers, you can keep track of the disk space available in a Parallels Cloud Storage cluster. To monitor chunk servers, use the pstorage -c <cluster_name> top command, for example:

Monitoring Chunk Server Parameters

The command above shows detailed information about the pcs1 cluster. The monitoring parameters for chunk servers (highlighted in red) are explained in the table below:

Parameter	Description
CSID	Chunk server identifier (ID).
STATUS	Chunk server status: active . The chunk server is up and running. Inactive . The chunk server is temporarily unavailable. A chunk server is marked as inactive during its first 5 minutes of inactivity. offline . The chunk server is inactive for more than 5 minutes. After the chunk server goes offline, the cluster starts replicating data to restore the chunks that were stored on the affected chunk server. dropped . The chunk serve was removed by the administrator.
SPACE	Total amount of disk space on the chunk server.
FREE	Free disk space on the chunk server.
REPLICAS	Number of replicas stored on the chunk server.
IOWAIT	Percentage of time spent waiting for I/O operations being served.
IOLAT	Average/maximum time, in milliseconds, the client needed to complete a single IO operation during the last 20 seconds.
QDEPTH	Average chunk server I/O queue depth.
HOST	Chunk server hostname or IP address.
FLAGS	The following flags may be shown for active chunk servers: `J` : The CS uses a write journal. `C` : Checksumming is enabled for the CS. Checksumming lets you know when a third party changes the data on the disk. `D` : Direct I/O, the normal state for a CS without a write journal. `c` : The chunk server's write journal is clean, there is nothing to commit from the write journalling SSD to the HDD where the CS is located. Note : Flags which may be shown for failed chunk servers are described in Failed Chunk Servers .

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