US 9,811,405 B2
Cache for file-based dispersed storage
Manish Motwani, Chicago, IL (US); and Ilya Volvovski, Chicago, IL (US)
Assigned to International Business Machines Corporation, Armonk, NY (US)
Filed by CLEVERSAFE, INC., Chicago, IL (US)
Filed on Jul. 8, 2014, as Appl. No. 14/325,425.
Application 14/325,425 is a continuation of application No. 12/903,209, filed on Oct. 13, 2010, granted, now 9,152,489.
Claims priority of provisional application 61/290,775, filed on Dec. 29, 2009.
Prior Publication US 2014/0325305 A1, Oct. 30, 2014
Int. Cl. G06F 11/07 (2006.01); G06F 21/10 (2013.01); G06F 12/0813 (2016.01); G06F 12/0815 (2016.01); G06F 11/14 (2006.01); G06F 11/10 (2006.01); G06F 9/46 (2006.01)
CPC G06F 11/0745 (2013.01) [G06F 9/467 (2013.01); G06F 11/1064 (2013.01); G06F 11/1092 (2013.01); G06F 11/1443 (2013.01); G06F 11/1471 (2013.01); G06F 12/0813 (2013.01); G06F 12/0815 (2013.01); G06F 21/10 (2013.01); G06F 2211/1028 (2013.01); G06F 2211/1057 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A method for execution by a computing device of a dispersed storage network (DSN), the method comprising:
retrieving, by the computing device, a first set of a decode threshold number of encoded data slices of a first set of encoded data slices in accordance with a read function regarding a file, wherein a first portion of the file is dispersed storage error encoded to produce the first set of encoded data slices;
decoding, by the computing device, the first set of a decode threshold number of encoded data slices to recover the first portion;
outputting, by the computing device, the recovered first portion in accordance with the read function;
performing, by the computing device, a read ahead operation regarding the file to identify a second portion of the file, wherein the second portion is dispersed storage error encoded into a second set of encoded data slices;
determining, by the computing device, to retrieve a second set of the decode threshold number of encoded data slices of the second set of encoded data slices from storage units of the DSN;
when determined to retrieve the second set of the decode threshold number of encoded data slices:
retrieving, by the computing device, the second set of the decode threshold number of encoded data slices; and
temporarily storing, by the computing device, the second set of the decode threshold number of encoded data slices;
determining, by the computing device, whether to output the second portion in accordance with the read function; and
when determined to output the second portion in accordance with the read function:
retrieving, by the computing device, the second set of the decode threshold number of encoded data slices from temporary storage;
decoding, by the computing device, the second set of the decode threshold number of encoded data slices to recover the second portion; and
outputting, by the computing device, the recovered second portion in accordance with the read function.