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Chaitanya Yalamanchili, Kiron Vijayasankar, Erez Zadok, Gopalan Sivathanu
2009 Proceedings of SYSTOR 2009: The Israeli Experimental Systems Conference on - SYSTOR '09  
A typical storage hierarchy comprises of components with varying performance and cost characteristics, providing multiple options for data placement. We propose and evaluate a hierarchical storage system, DHIS, that uses application-level hints to discriminate between data with different access characteristics, and then customizes its placement and caching policies to each type. The data placement decisions in DHIS are made in an online fashion, during data creation. Most existing solutions
more » ... attempt to customize data layout require moving data around, based on access characteristics. DHIS uses two kinds of information to make its decisions. First, it uses knowledge about higher-level pointers between blocks (for example, file system pointers) to understand the relationship between blocks and consequently, their importance. Second, DHIS defines a set of generic attributes that the higher layers can use to annotate data, conveying various properties such as importance, access pattern, etc. Based on these attributes, DHIS dynamically decides to place the data in the hierarchy best suited for its requirements. By doing so, DHIS solves a critical problem faced by storage vendors and developers of higher level storage software, in terms of choosing the most efficient policy among many alternatives. Through several benchmarks, we show that DHIS's data placement decisions improve performance significantly.
doi:10.1145/1534530.1534543 dblp:conf/systor/YalamanchiliVZS09 fatcat:tgzvgrpdu5fmjlylmf4nuqsbaa

Exploiting type-awareness in a self-recovering disk

Kiron Vijayasankar, Gopalan Sivathanu, Swaminathan Sundararaman, Erez Zadok
2007 Proceedings of the 2007 ACM workshop on Storage security and survivability - StorageSS '07  
Data recoverability in the face of partial disk errors is an important prerequisite in modern storage. We have designed and implemented a prototype disk system that automatically ensures the integrity of stored data, and transparently recovers vital data in the event of integrity violations. We show that by using pointer knowledge, effective integrity assurance can be performed inside a block-based disk with negligible performance overheads. We also show how semantics-aware replication of
more » ... can help improve the recoverability of data in the event of partial disk errors with small space overheads. Our evaluation results show that for normal user workloads, our disk system has a performance overhead of only 1-5% compared to traditional disks.
doi:10.1145/1314313.1314321 dblp:conf/storagess/VijayasankarSSZ07 fatcat:xmxc4nzeszchrlsnckas47utim