10-05-2012, 04:28 PM
THE LAST WORD IN FILE SYSTEMS
zfs_lc_preso.pdf (Size: 2.25 MB / Downloads: 125)
Trouble With Existing Filesystems
No defense against silent data corruption
● Any defect in disk, controller, cable, driver, or firmware can
corrupt data silently; like running a server without ECC memory
● Brutal to manage
● Labels, partitions, volumes, provisioning, grow/shrink, /etc/vfstab...
● Lots of limits: filesystem/volume size, file size, number of files,
files per directory, number of snapshots, ...
● Not portable between platforms (e.g. x86 to/from SPARC)
● Dog slow
● Linear-time create, fat locks, fixed block size, naïve prefetch,
slow random writes, dirty region logging
Free Your Mind
● Figure out why it's gotten so complicated
● Blow away 20 years of obsolete assumptions
● Design an integrated system from scratch
ZFS Design Principles
● Pooled storage
● Completely eliminates the antique notion of volumes
● Does for storage what VM did for memory
● End-to-end data integrity
● Historically considered “too expensive”
● Turns out, no it isn't
● And the alternative is unacceptable
● Transactional operation
● Keeps things always consistent on disk
● Removes almost all constraints on I/O order
● Allows us to get huge performance wins