|
As yet, no investigation has been done in this area. Open questions for discussion and resoultion include:
- do clients only connect to a single MGS, but perform some kind of round-robin selection of the target NID to use at mount, to distribute load among the MGS instances?
- how are config logs replicated between MGT instances?
- Using FLR layouts for the files on the MGT would re-use existing infrastructure, and give a clear indication of which is the primary mirror and which mirrors might be "stale" and need to be resync'd from the primary. On the flip side, this might complicate the replication.
- Using a llog consumer on the backup MGTs to read the config logs and store locally (as the MDT and OST llog copies are handled) would give more independence between the MGTs
- are the "backup" MGTs read-only, or could one of them take over in case the primary MGT fails? Or should there be a manual resync process from any of the backup MGTs if the primary is corrupted? There are not very many files on the MGT, so doing a full reformat/resync is relatively simple.
|