OceanStore & GPFS
(Redirected from Oceanstore & GPFS)
Readings
John Kubiatowicz et al., "OceanStore: An Architecture for Global-Scale Persistent Storage" (2000)
Sean Rhea et al., "Pond: the OceanStore Prototype" (2003)
Questions
Is it worth it??
Ocean Store
Pros
- Only trust required is own box
- Data is highly durable due to file versioning
- Information divorced from location
- So long as you can reliably obtain information, it doesn't matter where it is located
- Applicable to many data storage situations, not for a specific case
- Routing is decentralized
- 2/3 of network is up? All is available
Cons
- Very expensive to computer cryptography (slow generation of keys)
- Utility models don't make economic sense, people prefer not to pay for access to their data
GPFS
Distributed local OS designed for clusters Max size of 4096TB
Pros
- Massively parallel - data is striped across many many disks
- Therefor read/write is very fast
- Option of redundancy
- Locking mechanism
- Two options
- 1. Data shipping
- Distributed
- First client to request access to file receives token
- Other clients must request the current owner of the token
- The current owner of the file grants portional access to their file (breaks token and gives portion access)
- 2. Centralized locking
- Faster in a small disk circumstance
- 1. Data shipping
- Two options
- Extreme reliability
- Able to literally remove a hotswap disk and insert a blank one in its place, only to have the blank disk completely regenerate the missing data
- Journalling to record token ownership - helps recovery when node in possession dies
Cons
- Everything must be trusted! Designed for clusters, not across LAN/WAN
- Not appropriate for distributed networks.
XUFS
- User-space implementation
- Designed to be simple
- Very generic