Asynchronous data redundancy technique

<12) United States Patent

USOO738008lB2

(10) Patent No.: US 7,380,081 B2

Ji et al. (45) Date of Patent: May 27, 2008 (54) ASYNCHRONOUS DATA REDUNDANCY 2003/0135478 A1* 7/2003 Marshall et al. ............. .. 707/1 TECHNIQUE 2003/0225760 A1* 12/2003 Ruuth ct al. ................. .. 707/5 (75) Inventors: Minwen Ji, Sunnyvale, CA (US); Alistair Veitch, Mountain VieW, CA (US); John Wilkes, Palo Alto, CA (Us) QTHER PUBLICATIONS (73) Assignee: Hewlett-Packard Development 52035:; gaiggieiig’ 8S_e1c0uf,,ity in Computing’ 1997’ Prentice Han’ Company’ LP" Houston’ TX (US) Fay Chang, MinWen Ji, Shun-Tak A. Leung, John MacCormick, ( * ) Notice: Subject to any disclaimer the tenn of this ihfron E Pperl :31-d Ll 5 (e°S;'eee°i‘Ve gllsasteg ’ 0 erance, rocee in s 0 e on erence on 1 e an patent is extended or adjusted under 35 Storagae Technologiegs, Monterey, CA, pp. 103-116, The USENIX U~S~C~ 15403) by 590 day5~ Association, Berkeley, CA, Jan. 2002. Chia Chao, Robert English, David Jacobson, Alexander Stepanov, (21) APPi~ N05 10/4561345 and John Wilkes, Mime: a high performance parallel storage device _ With strong recovery guarantees, HP Laboratories Technical Report (22) Fllodi Jl1I1- 6, 2003 HPL-CSP-92-9 rev 1, Mar. 18, 1992, revised Nov. 6, 1992, HewlettPackard Company, Palo Alto, CA, 1992. (65) Prior Publication Data

US 2004/0250029 A1 Dec. 9, 2004

(51) Int. Cl.
G06F 12/00 (2006.01)
(52) U.S. Cl. ....................................... .. 711/162;710/52
(58) Field of Classification Search ............... .. 711/162
See application file for complete search history.
(56) References Cited
U.S. PATENT DOCUMENTS
5,544,347 A 8/1996 Yanai et al.
5,592,618 A * 1/1997 Micka et al. ............... .. 714/54
5,742,792 A 4/1998 Yanai et al.
5,909,692 A 6/1999 Yanai et al.
6,092,066 A 7/2000 Ofek
6,101,497 A 8/2000 Ofek
6,108,748 A 8/2000 Ofek et al.
6,260,125 B1* 7/2001 McDoWell ................ .. 711/162
6,397,307 B2* 5/2002 Ohran ...................... .. 711/161
6,405,294 B1* 6/2002 Hayter ..................... .. 711/162
6,496,908 B1 * 12/2002 Karnvysselis et al. 711/162
6,502,205 B1* 12/2002 Yanai et al. ................. .. 714/7
6,842,825 B2 * 1/2005 Geiner et al. 711/133
6,931,576 B2 * 8/2005 Morrison et al. ........... .. 714/54
2003/0101321 A1* 5/2003 Ohran ...................... .. 711/162

(Continued)

Primary Examiner—Donald Sparks
Assistant Examiner—MattheW Bradley

(57) ABSTRACT

A primary copy of data is held at a primary storage facility, While data that is redundant of the primary copy is held at a secondary storage facility. To inhibit propagation of errors from the primary copy to the redundant data, Write transactions to the redundant data are queued at the second storage facility, until a specified time elapses or until a specified event occurs (or until combination hereof occurs). Write transactions may be collected in groups at the primary facility prior to forWarding to the secondary facility and may also be batched at the secondary facility prior to being applied to the redundant data. OverWrites may be alloWed Within a group at the primary facility to conserve cominunication bandWidth betWeen the primary and secondary storage facilities. OverWrites may be alloWed Within a batch at the secondary facility to conserve space occupied by the transactions at the secondary facility.

38 Claims, 14 Drawing Sheets

~i \i\ 105
Secondary Storage Facility Q
Batch Batch Batch
' ' ' m+3 m+2 m+l