Group" LABCOM

H. "Nakanishi

M. Kojima

M. Nonomura

M. Ohsuna

S. Imazu

National Institute for Fusion Science (NIFS-Repository)

The LABCOM data acquisition and management system has been operating for LHD since 1998. In the 14thcampaign, the total number of the data acquisition (DAQ) nodes went up to 90, and more than half of them aresteady-state operable by using Yokogawa WE7x and NIPXI digitizers.Fig. 1 shows the history of data growth happened at LHD. In short-pulse experiments of less than 10-second plasma duration, ~11 GB/shot raw data are acquired. For more than ten years, the data growth very well follows the famous Moore’s law that predicts the data size to be double in every 18 months. It corresponds 100 times growth for 10 years, which can be observed well in Fig. 1 (left). As a result, the total amount of the cumulated data is increasingexponentially up to > 0.33 PB.Continuous Monitoring for Device and EnvironmentIn addition to the sequential data acquisition and storing during experiments, we have newly installed 24/7 non-stop signal monitoring DAQs for device status and environmental radiation dose monitoring.The so-called control device monitoring one named “CDP” carries out continuous 1 kHz digitizing on every 540 analog signals. They are mainly used for the cryogenics and temperature monitoring by thermocouples. CDP uses 7 of 80-channel multiplexed 16-bit ADC module, NI PXI-6225, contained in a PXI chassis. The raw data production rate will be560 ∗ 2 ∗ 103 ∗ 3600 ∗ 24 ∗ 7 = 0.677∗1012 byte/week, and thus >16 TB will be acquired in one annual campaign.For better accessibility of those trend data, 1 Hz thinned “CDPslow” and its day-long one “CDPslowL” are also made by smoothing the original signals. The both CDP and CDPslow data can be retrieved with the same manner for usual plasma diagnostic data except that their shot and sub-shot numbers are the date and time in digits, like 20110628 and 1827, respectively.Verification Tests on New “Cloud” StorageSince last year, we have introduced a new “cloud”storage system, named “IznaStor”1). It applies cost effective 10 GbE NAS (network attached storage) and provides some good functionalities of automatic internal file replication, load balancing, SPOF (single point of failure)-free high availability, anonymous hot plug-and-play nodes, and so on. See Table I.Table II shows the performance improvements by thecloud storage, which basically provides 4 or 6 times faster speed than 4 Gbps FC-based cluster storage. When it is used by means of FUSE (file-system in user-space) for the data server’s compatibility, the protocol conversion may cause some overheads to reduce the throughput. As newly acquired raw data are migrated through FTP client/server codes in LABCOM system, we will have to modify them to directly access the native functions of “IznaStor”.Table I. Functional comparison between FC-based cluster file-system (GFS2), IP-based iSCSI one, and the new cloud storage “IznaStor”GFS2/FC GFS2/iSCSI IznaStorCost +/− ++ ++ Speed +/− ++ ++ Scale out +/− +/− ++ Load balance −− −− ++ Availability +/− +/− ++ Fault tolerance −− −− ++ Table II. Throughput comparison between old GFS2 cluster storage vs. new “IznaStor” cloud oneStorage device / File-system I/O speed (MB/s)4 Gbps FC-RAID/RH-GFS2 10710 GbE IznaStor/FUSE vfs 17210 GbE IznaStor/native put - get 403 - 6201) Nakanishi, H. et al.: NIFS Annual Report (2010) 181.     Fig. 1.  Data growth in LHD: Acquired raw data size per shot (left) and the cumulated amount (right).140§20. Progress of LABCOM Data System at LHDNakanishi, H., Ohsuna, M., Kojima, M., Nonomura, M.,  Imazu, S. (Pretech Corp.),  LABCOM Group

Progress of LABCOM Data System at LHD

Abstract

Similar works

Full text

Available Versions

National Institute for Fusion Science (NIFS-Repository)