Hello Hiroki,  No - the protection is a mirror, two copies of the data.  Yes, you have to choose where to put your MDMs during the installation - but you can always add/remove MDMs afterwards. Thank you, Pawel
Hello,  1. Can ScaleIO have also three mirrored data protection or four mirrored data protection? Because I found the following.  "Protection domain A large ScaleIO storage pool can be divided into multiple protection domains, as shown in Figure 7, each of which contains a set of SDSs. ScaleIO volumes are assigned to specific protection domains. Protection domains can be used to mitigate the risk of a dual point of failure in a two-copy scheme, or a triple point of failure in a three-copy scheme." On page 27 of "EMC VSPEX PRIVATE CLOUD: VMware vSphere and EMC ScaleIO"  Even though I also found the following. "Protection and load balancing ScaleIO maintains the user data in a RAID-1 mesh mirrored layout. Each piece of data is stored on two different servers. The copies are randomly distributed over the storage devices. Rebuild and rebalance processes are fully automated, but are configurable." on page 28 of "EMC ScaleIO Installation Guide"  Are they above explaining about different topics?   2. Can we choose 3 or 5 servers to place MDM (Meta Data Manager) as one chooses otherwise they are chosen automatically? Does ScaleIO have five nodes option for installing the MDM component? "Even though I found the following so that it seems they can be chosen by manually. Note: MDMs do not require dedicated nodes. They can be installed on nodes hosting other ScaleIO components." On page 37 "EMC ScaleIO Installation Guide"   Best regards, Hiroki
Data protection & MDM placement