--- In [email protected], "Saifi Khan" <[EMAIL PROTECTED]> wrote: > > Hi all: > > I was reading a document on file system basics, when I came across the term 'File System migration'. > > It is described as - "technique to move a filesystem from one server to another." > > Can somebody explain what is the mechanism an how it works ? > > Thanks in advance. > > thanks > Saifi. >
Hi Saifi, The term FileSystem Migration usually refers to migration from one FileSystem to another. The technique of moving a file system from one server to another is usually referred to as "Data Migration". Typically data migration is required when two companies merge or data centers move from one vendor's storage to another. It could also be driven by new DR (Disaster Recovery) site requirements or ILM (Information Lifecycle Management) needs. Data migration due to the above reasons would involve movement of terabytes of data and migration windwows are not more than a weekend long. Hence, software solutions dont work well. However, the catch here is that data migration is a less frequent activity (usually a one time activity). So no customer will buy hardware specially for data migration. So vendors provide this feature as an add-on to already existing products. As far as the mechanism is concerned, that depends on where the feature is provided (as a part of which product). At the host end you can have it in software like the volume manager (Eg. Veritas VM) - just mirror the lun. On the storage end you can have the array or NAS appliance provide this feature (Eg. EMC SAN Copy). In this case you cannot migratie to another vendor's array, of course :-) On the network, you can have appliances (Eg. FalconStor's IPStor, which is a SAN Management appliance provides this feature as an add-on) or switches (eg. DMM (data migratio manager) - an addon to Brocade's Silkworm 68000). Typical performance expectation for data migration is 1TB an hour or more. This is only achievable thru block copy, which means reads would bypass the filesystem. Hence the term 'Filesystem migration' cannot be used in this case. Hope this helps, Namita
