DPM2010 scalability and "collocation and autogrow" features

Why the hassle about 300 data sources, the ‘LDM limit’ thing and where do new DPM2010 options “collocation” and “autogrow” come into play? The magic ‘300’ is a chosen limit that derives from the Logical Disk Manager number of volumes that can coexist on a Windows system. Note that DPM requires 2 volumes to protect […]

Why the hassle about 300 data sources, the ‘LDM limit’ thing and where do new DPM2010 options “collocation” and “autogrow” come into play? The magic ‘300’ is a chosen limit that derives from the Logical Disk Manager number of volumes that can coexist on a Windows system. Note that DPM requires 2 volumes to protect a data source, 1 for replica and 1 for recovery point volume. This means if we max out a supportable DPM server on this aspect there’ll be at least 600 volumes on system. LDM has a fixed size data structure (the ldm database) with records to define volumes that occupy at least 1 ‘slot’ and sometimes 2. To cut short, there’re 2960 slots available and each new volume requires 3 or 4 slots and 1 more for each time a volume is extended. Wait a minute, with 300 data sources requiring 600 volumes, that consumes 1800 out of 2960. In other words; you cannot extend all replicas and recovery point volumes twice on a maximum configuration. Not that this’s likely to occur but chances increase with DPM2010 as we’ll see[…]

More info: About DPM2010 scalability and new features