wiki:pingJMD
Last modified 9 years ago Last modified on 02/10/14 11:12:19

Pinging the JMD

The "wget" utility can be used to "ping" the JMD to make sure it is responding. The command :

wget http://localhost:8080/JMD/JMD

when run on the machine that is running the JMD should write a file named "JMD" that is the JMD's response when it is queried with no arguments (which is simply to list some of the parameters it is running with). The file should look something like this :

MIRROR POOL TOTAL THREADS:30
MIRROR POOL QUEUE size:0
MIRROR POOL ACTIVE THREADS:0
MIRROR POOL THREADS AVAIL:30
USER POOL TOTAL THREADS:30
USER POOL QUEUE size:0
USER POOL ACTIVE THREADS:0
USER POOL THREADS AVAIL:30
NEW=0
QUEUED=0
READY=0
PENDING=0
DONE=2
TIMEOUT=0
FAILED=0
AVERAGE_DOWNLOAD=9.905377 MB/s

This is a very basic first step, and only establishes basic connectivity. A better test involves interacting with some data. This can be done with the show_info command. Both show_info and the underlying idea of storage unit numbers (sunums) are beyond the scope of this discussion, and are introduced here only in passing. For now, we use show_info to identify data that we do not have on disk already. The command :

show_info -S -P key=T_OBS,T_REC_INDEX,WAVELNTH ds='aia.lev1[2011-08-19T10:59:57Z/1m][?wavelnth=304?]'

will return something like this if the data are already on disk :

sunum   T_OBS   T_REC_INDEX     WAVELNTH        SUDIR
236661975       2011-08-19T10:59:57.57Z 1092826832      304     /SUM02/D236661975/S00000
236662019       2011-08-19T11:00:09.57Z 1092826844      304     /SUM02/D236662019/S00000
236662008       2011-08-19T11:00:21.57Z 1092826856      304     /SUM01/D236662008/S00000
236662040       2011-08-19T11:00:33.59Z 1092826868      304     /SUM02/D236662040/S00000
236662058       2011-08-19T11:00:45.57Z 1092826880      304     /SUM01/D236662058/S00000

but will not list the directories where the data reside if the data are not on disk :

sunum   T_OBS   T_REC_INDEX     WAVELNTH        SUDIR
236661975       2011-08-19T10:59:57.57Z 1092826832      304
236662019       2011-08-19T11:00:09.57Z 1092826844      304
236662008       2011-08-19T11:00:21.57Z 1092826856      304
236662040       2011-08-19T11:00:33.59Z 1092826868      304
236662058       2011-08-19T11:00:45.57Z 1092826880      304

If we find some data that are not on disk, then we can initiate a JMD download of the data by using the "-p" rather than the "-P" option with show_info, like this :

show_info -S -p key=T_OBS,T_REC_INDEX,WAVELNTH ds='aia.lev1[2011-08-19T10:59:57Z/1m][?wavelnth=304?]'

The download should then appear in the JMD log, and subsequently running show_info with "-P" should show the data to be on disk locally.

If requesting the data with show_info fails, this may indicate the the JMD is running but is not contactable through show_info. To query the database directly, use the jmd_admin.pl script to request the data directly from the JMD :

jmd_admin.pl --request -- --series=aia.lev1 --sunums= 236661975, 236662019, 236662008, 236662040, 236662058 --priority=20