Posts

Why you should always use DRAID

Hello friends - I have been a bit focussed on remote copy lately so this week I would like to shake things up a bit and provide a simple explanation as to why you should always use Distributed RAID over Traditional RAID in Spectrum Virtualize products.
Traditional RAID This is what we typically refer to as RAID in the storage industry as a whole. We aggregate drives and either stripe data or mirror it across multiple physical drives. In the Spectrum Virtualize platforms we generally support: RAID 0 - Striping data across drives for maximum performance with no redundancySince all drives hold unique data, we only write once providing best write performanceDoes not allow for any drives in the array to fail without data lossRAID 1 - Mirroring data across drives (normally 2) to provide redundancyWrites the same data set across a pair of drives requiring data to be written twiceAllows for one drive in the mirrored set to fail without losing dataRAID 5 - Striping data across drives providing …

Remote Copy Data Patterns and Partnership Tuning

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Hello friends. I know it has been a while, but I would like to now put out part 2 to the 1920 post I had put out a while back. That post was largely around tuning the partnership to protect against impacts to the master volume (or replication source). This week I would like to explain a bit about how data is replicated to help understand why 1920 events and backpressure can happen and how to hopefully avoid the situation in the first place.
Types of Remote Copy Relationships in SpecV Metro Mirror (Synchronous/Synchronous) Metro Mirror is what I call a Sync/Sync replication. By this I mean that the RPO is synchronous or in layman's terms the two sides of the mirror are always identical. Additionally, the data pattern for the replication is synchronous as well meaning we forward new writes as we receive them as shown here: