A fourth source has added new insight into Microsoft’s Danger datacenter disaster, pinning the root cause directly on Pink Project leader Roz Ho rather than Microsoft’s third party vendors, which the company is itself seeking to scapegoat.
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Existing reports have all described Microsoft’s Danger datacenter problem as resulting from a maintenance event related to a failed SAN firmware update. The story is that the SAN update failed and Microsoft was subsequently unable to restore the data from backup. This leaves a lot unanswered; fortunately, the new source fills in those gaps.

Link: http://www.roughlydrafted.com/2009/10/15/microsofts-pinkdanger-backup-problem-blamed-on-roz-ho/

Information on what happened is available over at CNET