1.What is ISIS
ISIS is consisted of: system directors,engines and clients.
1.1 system director is like a traffic cop. it store directory information and file attributes. actul data is stored on the ISBs.
1.2 engine include ISB,ISS,IXS.
2. What is blade
"blade" is field replacable unit(FRU)
there are 16 blades in each engine.
there are 2 disks per blade
3. What is chassis
3.1 each engine is based on one chassis. ISIS support up to 12 engines/chassis. There are 16 storage blades per chassis.
3.2 there are two switches per chassis.
3.3
4. 12*16*2TB=384TB
5. What is chunk,sub chunk
512k,file is broken into a serial of logical blocks--"chunk".
Chunk = Unit of allocation per uServer
Sub chunk = Unit of allocation per disk
6. What is RAID6
– • Pick 2 servers for redundancy info for a group (superchunk) of 6 data chunks redundancy: repetition of messages to reduce the probability of errors in transmission 7. file map 7.1 The term file map is frequently used as short hand for a collection of structures • 7.2 File map h as unique ID propagated through the system with File ID 8. What is seed 9. Redistribution redistribution is needed only to add or remove servers from a storage group 10. Microserver Slide 5 – 10.1 Stores data in fixed size chunks – 10.2 Redistributes data – 10.3 Linux on ISIS 7000 blades , Windows Server on ISIS 5000 11. ISIS 5000 is simpler than ISIS7000 • 11.1 Hardware RAID within a server – no distributed RAIN
11.2 little configuration flexibility
11.3 redistribution is needed only to add or remove servers from a storage group
11.4 lower availability and relaibility
(1) system director failures make data unavailable
(2) one uServer failure makes data unavailable
(3) two disks failure can cause data loss
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