Storage information in the Site Status Board

This page explains the information published in the SSB via a specialized view called 'storage'.

First of all, a Data Service query returning all PhEDEx nodes is used to:

• find all nodes in a site
• the SE for each node

Second, the BDII is queried, and for all Storage Areas supporting CMS in a given PhEDEx site we sum up the following attributes:

• GlueSATotalOnlineSize
• GlueSAFreeOnlineSize
• GlueSAUsedOnlineSize
• GlueSATotalNearlineSize
• GlueSAFreeNearlineSize
• GlueSAUsedNearlineSize
• InstalledOnlineCapacity
• InstalledNearlineCapacity

The used space should measure the amount of storage capacity in use, while the free space is defined as the total capacity minus the used capacity. The total space is the same as the installed capacity only if all disk servers are up.

Third, for each site with PhEDEx nodes, we use queries like

https://cmsweb.cern.ch/phedex/datasvc/xml/prod/nodeusage?node=$node

to extract these parameters:

• cust_node_bytes
• cust_dest_bytes
• noncust_dest_bytes
• noncust_node_bytes

and define

incoming      = cust_dest_bytes + noncust_dest_bytes - cust_node_bytes - noncust_node_bytes
custodial     = cust_node_bytes
non_custodial = noncust_node_bytes

The following table summarizes all columns in the SSB and describes when a value is marked red (meaning an error condition)

Column name	Definition	Red when	Yellow when
Disk pledge (TB)	Pledged disk resources from SiteDB (TB)	> 1 year old	> 1 quarter old
Tape pledge (TB)	Pledged tape resources from SiteDB (TB)	> 1 year old	> 1 quarter old
Used disk (TB)	Total used disk from BDII	< 1 TB or no info
Installed disk (TB)	Installed Online capacity from BDII	< 10 TB or no info	2 * abs(installed - total) / (installed + total) > 10%
Total disk (TB)	Total disk from BDII	< 10 TB or no info	abs(total - used - free) > 10%
Free disk (TB)	Total free disk from BDII	< 10 TB or no info
Custodial (TB)	PhEDEx custodial data
Non-Custodial (TB)	PhEDEx non-custodial data
Incoming (TB)	Subscribed data not on site
Used tape (TB)	Total used tape from BDII	tier-0/1 and < 1 TB or no info
Installed tape (TB)	Installed Nearline capacity from BDII	tier-0/1 and < 10 TB or no info	2 * abs(installed - total) / (installed + total) > 10%
Total tape (TB)	Total tape from BDII	tier-0/1 and < 10 TB or no info	abs(total - used - free) > 10%
Free tape (TB)	Total free tape from BDII	tier-0/1 and < 10 TB or no info

-- AndreaSciaba - 04-Oct-2011