Managing Thermal Emergencies in Disk-Based Storage Systems

2008 ◽  
Vol 130 (4) ◽  
Author(s):  
Youngjae Kim ◽  
Jeonghwan Choi ◽  
Sudhanva Gurumurthi ◽  
Anand Sivasubramaniam
Keyword(s):  
Thermal Management ◽  
Air Temperature ◽  
Storage Systems ◽  
Storage System ◽  
Disk Drive ◽  
Disk Drives ◽  
Unexpected Events ◽  
Worst Case ◽  
Average Case ◽  
Dynamic Thermal Management

Thermal-aware design of disk-drives is important because high temperatures can cause reliability problems. Dynamic thermal management (DTM) techniques have been proposed to operate the disk at the average case temperature, rather than at the worst case by modulating the activities to avoid thermal emergencies caused by unexpected events, such as fan-breaks, increased inlet air temperature, etc. A delay-based approach to adjust the disk seek activities is one such DTM solution for disk-drives. Even if such a DTM approach could overcome thermal emergencies without stopping disk activity, it suffers from long delays when servicing the requests. In this paper, we investigate the possibility of using a multispeed disk-drive (called dynamic rotations per minute (DRPM)), which dynamically modulates the rotational speed of the platter for implementing the DTM technique. Using a detailed performance and thermal simulator of a storage system, we evaluate two possible DTM policies—time-based and watermark-based—with a DRPM disk-drive and observe that dynamic RPM modulation is effective in avoiding thermal emergencies. However, we find that the time taken to transition between different rotational speeds of the disk is critical for the effectiveness of this DTM technique.

System Dynamics and Disk Drive Head Position Error Prediction in a Data Storage Box

2014 ◽  
Author(s):  
Lidu Huang ◽  
Chiao-ping Roger Ku ◽  
Jean O’Young ◽  
Toshiki Hirano
Keyword(s):  
Data Storage ◽  
Storage System ◽  
Disk Drive ◽  
Head Position ◽  
Position Error ◽  
System Level ◽  
Disk Drives ◽  
Data Storage System ◽  
Mechanical Disturbances ◽  
System Transfer Function

Disk drives are packed at ever dense arrangement in a modern data storage system, internal and external mechanical disturbances can have a great effect to disk drive’s read and write performances. The VCM torque generated during seeking affects its own as well as neighboring drives head position. In this study, we modeled a storage box with multiple HDDs installed to obtain mechanical system transfer function. The mechanical excitation is characterized by VCM torque, and HDD operational vibration behaviors on linear and rotational shakers are measured. A system level hybrid method predicting HDD head position error in a data storage box is described, and both analytical and measured results will be presented.

Constraint Allocation on Hierarchical Storage Systems

2011 ◽  
pp. 187-206
Author(s):  
Phillip K.C. Tse
Keyword(s):  
Storage Systems ◽  
Storage System ◽  
Data Migration ◽  
Access Time ◽  
Worst Case ◽  
Exchange Time ◽  
Multimedia Streams ◽  
Hierarchical Storage ◽  
The Media ◽  
Migration Method

Multimedia objects are stored on hierarchical storage systems (HSS). The objects are large in size but the access latency of HSS is high. It is necessary to provide high throughput in delivering data from the storage system. In addition to the statistical placement and striping methods in the two previous chapters, constraint allocation can also improve the throughput of HSS. Multimedia streams should be displayed with continuity. Depending on the data migration method, the whole object or only partial object is retrieved prior to the beginning of consumption. Thus, it may need to retrieve the parts of the object within guarantee times. The maximum access time depends on the storage locations of the object. If the parts of the object are freely stored on any media units, it may take the longest exchange time to exchange a media unit. If the parts of the object are freely stored on any locations of the media units, it may take the longest reposition time to reposition the media unit. The maximum access time needs to include both the longest exchange time and the longest reposition time. As a result, the guarantee times should not be shorter than the maximum access time in the worst case. The long guarantee time results in a small number of acceptable streams to the hierarchical storage system. The constraint allocation methods limit the freedom to place data on media units so that the worst case would never happen. They reduce the longest exchange time and/or the longest reposition time in accessing the objects. Two approaches to provide constraint allocations have been proposed on different types of media units. The interleaved contiguous placement limits the storage locations of data stripes on optical disks and it is described in the next section. The concurrent striping method that limits the storage locations of data stripes on tapes is described.

Heat Transfer Enhancement by Helium Gas Filled in a Hard Disk Drive Enclosure

2010 ◽  
Author(s):  
Jiaping Yang ◽  
Cheng Peng Tan ◽  
Eng Hong Ong
Keyword(s):  
Heat Transfer ◽  
Thermal Management ◽  
Hard Disk Drive ◽  
Data Storage ◽  
Data Center ◽  
Hard Disk ◽  
Disk Drive ◽  
Disk Drives ◽  
Transfer Enhancement ◽  
Helium Gas

Heat transfer issue has become a challenging task in designing a high power density data center. As power consumption (Watts) of the data center continues to increase, effective thermal management of computing clusters, servers and data storage systems in data center will become more and more demanding. Hard disk drive (HDD) as a key power consumption device in high-end data storage system, its heat transfer issue has attracted more research attentions due to its complexity in nature of enclosure air flow driven by spinning disks. Among various thermal management solutions, one promising approach is to enclose helium rather than air in the hermetically-sealed hard disk drive as to reduce windage loss and flow disturbance. This paper investigates the thermal performances of disk drives where their enclosures have been filled up with helium and various helium-air gas mixtures using FEM simulations and experimental validations. Windage loss and heat convection of the disk drives being filled up with helium or helium-air mixtures are compared and analysed. The results show that helium-filled HDD provides heat transfer enhancement capability than the air-filled HDD by achieving up to 41% reduction of average temperature rise. Furthermore, 40% reduction of magnetic transducer position error signals (PES) was experimentally observed in helium filled HDD. Enhancing heat transfer and better PES quality via helium gas will greatly improve HDD read/write reliability and increase track density capability for data storage systems in data center.

Hybrid Disk Drive Configuration on Database Server Virtualization

2016 ◽  
Vol 2 (3) ◽  
pp. 720
Author(s):  
Ferdy Nirwansyah ◽  
Suharjito Suharjito
Keyword(s):  
Storage System ◽  
Disk Drive ◽  
Sql Server ◽  
Disk Drives ◽  
Hybrid Storage ◽  
Server Virtualization ◽  
Database Server ◽  
Windows Server ◽  
Hybrid Configuration ◽  
Storage Technologies

SSD is a revolutionary new storage technologies. Enterprise storage system using full SSD is still very expensive, while HDD is still widely used. This study discusses hybrid configuration storage in virtualized server database with benchmark against four hybrid storage configuration for four databases, ORACLE, SQL Server, MySQL and PostgreSQL on Windows Server virtualization. Benchmark using TPC-C and TPC-H to get the best performance of four configurations were tested. The results of this study indicate HDD storage configurations as visual disk drive OS and SSD as visual disk drives database get better performance as OLTP and OLAP database server compared with SSD as visual disk drive OS and HDD as a visual disk drive database. Based on the data research TPC-C, OLTP get best performance at HDD storage configurations as visual disk drive OS and SSD as a visual disk drives database and temporary files.

Modeling an Energy Storage System Based on a Hybrid Renewable Energy System in Stand-alone Applications

2017 ◽  
Vol 68 (11) ◽  
pp. 2641-2645
Author(s):  
Alexandru Ciocan ◽  
Ovidiu Mihai Balan ◽  
Mihaela Ramona Buga ◽  
Tudor Prisecaru ◽  
Mohand Tazerout
Keyword(s):  
Renewable Energy ◽  
Energy Storage ◽  
Storage Systems ◽  
Renewable Energy Sources ◽  
Storage System ◽  
Energy Storage System ◽  
Compressed Air ◽  
Energy Sources ◽  
Energy Storage Systems ◽  
Hybrid Renewable Energy System

The current paper presents an energy storage system that stores the excessive energy, provided by a hybrid system of renewable energy sources, in the form of compressed air and thermal heat. Using energy storage systems together with renewable energy sources represents a major challenge that could ensure the transition to a viable economic future and a decarbonized economy. Thermodynamic calculations are conducted to investigate the performance of such systems by using Matlab simulation tools. The results indicate the values of primary and global efficiencies for various operating scenarios for the energy storage systems which use compressed air as medium storage, and shows that these could be very effective systems, proving the possibility to supply to the final user three types of energy: electricity, heat and cold function of his needs.

Rule Based Classifiers for Suspect Detection from CCTV Footages

2020 ◽  
Vol 13 ◽  
Author(s):  
Sunil Pathak
Keyword(s):  
Answer Sheet ◽  
Normal Activity ◽  
Contact Detection ◽  
Accuracy Rate ◽  
Hand Detection ◽  
Worst Case ◽  
Average Case ◽  
The Face ◽  
Case Simulation ◽  
Material Exchange

Background: The significant work has been present to identify suspects, gathering information and examining any videos from CCTV Footage. This exploration work expects to recognize suspicious exercises, i.e. object trade, passage of another individual, peeping into other's answer sheet and individual trade from the video caught by a reconnaissance camera amid examinations. This requires the procedure of face acknowledgment, hand acknowledgment and distinguishing the contact between the face and hands of a similar individual and that among various people. Methods: Segmented frames has given as input to obtain foreground image with the help of Gaussian filtering and background modeling method. Suh foreground images has given to Activity Recognition model to detect normal activity or suspicious activity. Results: Accuracy rate, Precision and Recall are calculate for activities detection, contact detection for Best Case, Average Case and Worst Case. Simulation results are compare with performance parameter such as Material Exchange, Position Exchange, and Introduction of a new person, Face and Hand Detection and Multi Person Scenario. Conclusion: In this paper, a framework is prepared for suspect detection. This framework will absolutely realize an unrest in the field of security observation in the training area.

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