Table~\ref{tab:disk} shows the situation of disk storage resources at CERN and Tier 1 sites, as well as at each Tier 1 site, as of February 11$^{\rm th}$ 2019. The used space includes derived data, i.e. DST and micro-DST of both real and simulated data, and space reserved for users. The latter accounts for 1.2 PB in total, 0.9 of which are used. The SRR disk used and SRR disk free information concerns only permanent disk storage (previously known as “T0D1”). The first two lines show a good agreement between what the site reports and what the LHCb accounting (first line) reports. The sum of the Tier 0 and Tier 1 sites 2018 pledges amount to 37.7 PB. The available disk space is 35 PB in total, 26 PB of which are used to store real and simulated datasets, and user data. A total of 3.7PB is used as tape buffer, the remaining 5 PB are free and will be used to store the output of the legacy stripping campaigns of Run1 and Run2 data that are currently being prepared. The disk space available at CNAF is about 6.6 PB, about 18\% above the pledge.
Table~\ref{tab:disk} shows the situation of disk storage resources at CERN and Tier 1 sites, as well as at each Tier 1 site, as of February 11$^{\rm th}$ 2019. The used space includes derived data, i.e. DST and micro-DST of both real and simulated data, and space reserved for users. The latter accounts for 1.2 PB in total, 0.9 of which are used. The SRR disk used and SRR disk free information concerns only permanent disk storage (previously known as “T0D1”). The first two lines show a good agreement between what the site reports and what the LHCb accounting (first line) reports. The sum of the Tier 0 and Tier 1 sites 2018 pledges amount to 37.7 PB. The available disk space is 35 PB in total, 26 PB of which are used to store real and simulated datasets, and user data. A total of 3.7PB is used as tape buffer, the remaining 5 PB are free and will be used to store the output of the legacy stripping campaigns of Run1 and Run2 data that are currently being prepared. The disk space available at CNAF is about 6.6 PB, about 18\% above the pledge.
In summary, the usage of computing resources in the 2018 calendar year has been quite smooth for LHCb. Simulation is the dominant activity in terms of CPU work. Additional unpledged resources, as well as clouds, on-demand and volunteer computing resources, were also successfully used. They were essential
in providing CPU work during the outage of the CNAF Tier 1 center. As for the INFN Tier 1 at CNAF, it came back to its fully-operational status in March 2018. After that, the backlog in the restripping campaign due to unavailability of data stored at CNAF was recovered, thanks also to the contribution of other sites, in time for the restart of data taking. After March 2018, CNAF operated in a very efficient and reliable way, being even able to over perform in terms of CPU power with respect to the pledged resources.
