Thats a unique idea.You should consider the following idea to enhance your idea so that it would impact uniquely: Disk access patterns are becoming ever more important to understand as the gap beten processor and disk performance increases. The study presented here is a detailed characterization of every lowlevel disk access generated by three quite different systems over a two month period. The contributions of this paper are the detailed information  provide about the disk accesses on these systems (many of our results are significantly different from those reported in the literature, which provide summary data only for file-level access on small-memory systems); and the analysis of a set of optimizations that could be applied at the disk level to improve performance. Our traces show that the majority of all operations are writes; disk accesses are rarely sequential; 25‐ 50% of all accesses are asynchronous; only 13‐41% of accesses are to user data (the rest result from swapping, metadata, and program execution); and I/O activity is very bursty: mean request queue lengths seen by an incoming request range from 1.7 to 8.9 (1.2‐1.9 for reads, 2.0‐14.8 for writes), while  saw 95th percentile queue lengths as large as 89 entries, and maxima of over 1000. Using a simulator to analyze the effect of write caching at the disk level,  found that using a small non-volatile cache at each disk allod writes to be serviced considerably faster than with a regular disk. In particular, short bursts of writes go much faster ‐ and such bursts are common: writes rarely come singly. Adding even 8 KB of non-volatile memory per disk could reduce disk traffic by 10‐ 18%, and 90% of metadata write traffic can be absorbed with as little as 0.2 MB per disk of nonvolatile RAM. Even 128KB of NVRAM cache in each disk can improve write performance by as much as a factor of three. FCFS scheduling for the cached writes gave better performance than a more advanced technique at small cache sizes. Our results provide quantitative input to people investigating improved file system designs (such as log-based ones), as ll as to I/O subsystem and disk controller designers.
['Chris Ruemmler', 'John Wilkes']
I am writing a research paper on a idea UNIX disk access patterns
[{"from": "human", "value": "I am writing a research paper on a idea UNIX disk access patterns"}, {"from": "gpt", "value": "Thats a unique idea.You should consider the following idea to enhance your idea so that it would impact uniquely: Disk access patterns are becoming ever more important to understand as the gap beten processor and disk performance increases. The study presented here is a detailed characterization of every lowlevel disk access generated by three quite different systems over a two month period. The contributions of this paper are the detailed information  provide about the disk accesses on these systems (many of our results are significantly different from those reported in the literature, which provide summary data only for file-level access on small-memory systems); and the analysis of a set of optimizations that could be applied at the disk level to improve performance. Our traces show that the majority of all operations are writes; disk accesses are rarely sequential; 25\u2010 50% of all accesses are asynchronous; only 13\u201041% of accesses are to user data (the rest result from swapping, metadata, and program execution); and I/O activity is very bursty: mean request queue lengths seen by an incoming request range from 1.7 to 8.9 (1.2\u20101.9 for reads, 2.0\u201014.8 for writes), while  saw 95th percentile queue lengths as large as 89 entries, and maxima of over 1000. Using a simulator to analyze the effect of write caching at the disk level,  found that using a small non-volatile cache at each disk allod writes to be serviced considerably faster than with a regular disk. In particular, short bursts of writes go much faster \u2010 and such bursts are common: writes rarely come singly. Adding even 8 KB of non-volatile memory per disk could reduce disk traffic by 10\u2010 18%, and 90% of metadata write traffic can be absorbed with as little as 0.2 MB per disk of nonvolatile RAM. Even 128KB of NVRAM cache in each disk can improve write performance by as much as a factor of three. FCFS scheduling for the cached writes gave better performance than a more advanced technique at small cache sizes. Our results provide quantitative input to people investigating improved file system designs (such as log-based ones), as ll as to I/O subsystem and disk controller designers."}]