# US 10,503,429 B2 · System and method for reference tracking garbage collector > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,503,429 B2 - Document ID: US10503429B2 - Status: Granted - Kind: B2 - Application number: 15/348,555 - Filed: 2016-11-10 - Published: 2017-10-05 - Granted: 2019-12-10 - Earliest claimed: 2016-11-10 - Assignees: EMC IP Holding Company LLC - Applicants: Emc IP Holding Company LLC - Inventors: Mikhail Danilov; Nikita Gutsalov; Alexander Fedorov; Konstantin Buinov; Gregory Skripko - Web page: https://patentgrep.com/patent/US10503429B2 ## CPC - G06F 3/0652: {Erasing, e.g. deleting, data cleaning, moving of data to a wastebasket} - G06F 3/0608: {Saving storage space on storage systems} - G06F 3/064: {Management of blocks} - G06F 3/067: {Distributed or networked storage systems, e.g. storage area networks [SAN], network attached storage [NAS]} - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A method, computer program product, and computer system for determining, by a computing device, that an object of a plurality of objects is an orphan. It may be determined that the object is older than a threshold age. A capacity occupied by the object may be reclaimed based upon, at least in part, determining that the object is an orphan and determining that the object is older than the threshold age. ## Claims ### Claim 1 A computer-implemented method comprising: maintaining, via a computing device, a first journal, wherein the first journal includes a content address that references an object when the object is created; maintaining a second journal, wherein the second journal includes a content address of a file that references the object when the object is deleted; updating a directory table associated with the second journal including the content address of the file that references the object when the object is deleted; determining that the object of a plurality of objects is an orphan based upon, at least in part, the first and second journals, at the time the directory table is updated; determining that the object is older than a threshold age, wherein upon determining that the object is older than the threshold age, removing a file having the content address that references the object from the first journal; reclaiming a capacity occupied by the object based upon, at least in part, determining that the object is an orphan and determining that the object is older than the threshold age; and determining, upon a triggering event, at least one of a total number of potential orphans exceeds a threshold of potential orphans, and a total capacity occupied by the potential orphans exceeds a threshold of total capacity. ### Claim 2 (depends on 1) The computer-implemented method of claim 1 wherein the object is a Binary Large Object (BLOB). ### Claim 3 (depends on 1) The computer-implemented method of claim 1 further comprising maintaining a set of one or more positive references to the object populated from the first journal. ### Claim 4 (depends on 3) The computer-implemented method of claim 3 further comprising maintaining a set of one or more negative references to the object populated from the second journal. ### Claim 5 (depends on 4) The computer-implemented method of claim 4 wherein determining that the object is an orphan includes determining that the set of one or more positive references to the object populated from the first journal compensates the set of one or more negative references to the object populated from the second journal. ### Claim 6 A computer program product residing on a non-transitory computer readable storage medium having a plurality of instructions stored thereon which, when executed across one or more processors, cause at least a portion of the one or more processor to perform operations comprising: maintaining a first journal, wherein the first journal includes a content address that references an object when the object is created; maintaining a second journal, wherein the second journal includes a content address of a file that references the object when the object is deleted; updating a directory table associated with the second journal including the content address of the file that references the object when the object is deleted; determining that the object of a plurality of objects is an orphan based upon, at least in part, the first and second journals, at the time the directory table is updated; determining that the object is older than a threshold age, wherein upon determining that the object is older than the threshold age, removing a file having the content address that references the object from the first journal; reclaiming a capacity occupied by the object based upon, at least in part, determining that the object is an orphan and determining that the object is older than the threshold age; and determining, upon a triggering event, at least one of a total number of potential orphans exceeds a threshold of potential orphans, and a total capacity occupied by the potential orphans exceeds a threshold of total capacity. ### Claim 7 (depends on 6) The computer program product of claim 6 wherein the object is a Binary Large Object (BLOB). ### Claim 8 (depends on 6) The computer program product of claim 6 further comprising maintaining a set of one or more positive references to the object populated from the first journal. ### Claim 9 (depends on 8) The computer program product of claim 8 further comprising maintaining a set of one or more negative references to the object populated from the second journal. ### Claim 10 (depends on 9) The computer program product of claim 9 wherein determining that the object is an orphan includes determining that the set of one or more positive references to the object populated from the first journal compensates the set of one or more negative references to the object populated from the second journal. ### Claim 11 A computing system including one or more processors and one or more memories configured to perform operations comprising: maintaining a first journal, wherein the first journal includes a content address that references an object when the object is created; maintaining a second journal, wherein the second journal includes a content address of a file that references the object when the object is deleted; updating a directory table associated with the second journal including the content address of the file that references the object when the object is deleted; determining that the object of a plurality of objects is an orphan based upon, at least in part, the first and second journals, at the time the directory table is updated; determining that the object is older than a threshold age, wherein upon determining that the object is older than the threshold age, removing a file having the content address that references the object from the first journal; reclaiming a capacity occupied by the object based upon, at least in part, determining that the object is an orphan and determining that the object is older than the threshold age; and determining, upon a triggering event, at least one of a total number of potential orphans exceeds a threshold of potential orphans, and a total capacity occupied by the potential orphans exceeds a threshold of total capacity. ### Claim 12 (depends on 11) The computing system of claim 11 further comprising maintaining a set of one or more positive references to the object populated from the first journal. ### Claim 13 (depends on 12) The computing system of claim 12 further comprising maintaining a set of one or more negative references to the object populated from the second journal. ### Claim 14 (depends on 13) The computing system of claim 13 wherein determining that the object is an orphan includes determining that the set of one or more positive references to the object populated from the first journal compensates the set of one or more negative references to the object populated from the second journal.