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Systems Engineering at HPCRDGary Leong HPCRD Systems Engineer High Performance Computing Research Lawrence Berkeley National Laboratory

High Performance Computing Research Department

The High Performance Computing Research Department conducts research and development in mathematical modeling, algorithmic design, software implementation, and system architectures, and evaluates new and promising technologies.C O M P U T A T I O N A L R E S E A R C H D I V I S I O N

ZFS Why? HPCRD research new technologies

seeks to optimize the performance, redundancy, and scalability of current hardware Benefits and alternative to current filesystems (e.g. ext2,3, ufs, reiserfs ZFS already tentatively embraced by the Unix community Apple, Linux Open Source MPL Disksuite not quite a commercial/enterprise level product. I.e. performance, redundancy, scalability Alternative, Third Party, Veritas Volume Manager Expensive Not simple to administer Finally, Sun offers a enterprise level filesystem Features similar to Veritas without the high cost and fully integrated into OS, and portable. C O M P U T A T I O N A L R E S E A R C H D I V I S I O N

ZFS At a glance Zettabyte File System 128 Bit file system - 16 billion billion times that of 64

bit file system (Huge Capacity) Pooled storage shared bandwidth (I/O) and capacity Increased performance over traditional volume managers (Filesystem + VM + RAID) Transaction Operation Copy on Write (No Journaling) Snapshots (ro) and Clones (rw) End to End Data Integrity Data Checksumed Administration ease (Integration of services)C O M P U T A T I O N A L R E S E A R C H D I V I S I O N

ZFS is like Virtual Memory

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ZFS VM similarity

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ZFS Volumes and Pool Storage

Traditional Volumes

-One to one ratio between FS to Volume

ZFS Pool Storage

-Pool Storage expand/shrink automatically -Shared Bandwidth (I/O) -Many FS to Storage Pool ratioC O M P U T A T I O N A L R E S E A R C H D I V I S I O N

ZFS is like a merged FS w/ RAID/Volume manager

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ZFS is like an attached NAS

Think of having a NAS with its integrated filesystem, RAID, and other features attached locally, directly to VFS instead of through the network.

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ZFS NAS like elaborated Most similar to NAS w/o the network

not an external storage and not quite a NAS box

Similar to NetApp in features (software based instead of

hardware based) Integrated RAID/VM (Pooled Storage) derivative of WAFL (Write Anywhere File Layout) Copy on Write no need for fsck/journaling - always consistent on disk

Snapshots and Clones very fast backups changes are kept track, rather than copy entire tree

Central Administration

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ZFS - Copy on Write (COW)

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ZFS - Central Administration Pool and filesystem created through zfs administration - no

need for format/fdisk and newfs/mkfs Automatic mounts - no need to manually enter in /etc/vfstab or use mount command Checksum enabled/disabled through zfs administration Quotas centralized in zfs administration Compression enabled/disabled in zfs administration NFS shared through zfs administration Snapshots and clones through zfs administration Backup (Full and Incremental snapshots) through zfs administration

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ZFS - Other notable features All data checksumed

Self Healing (mirror) Disk Scrubbing Object Based Transactions WAFL - data can be written on any location on disk Not block by block changes, but aggregate changes to objects (transaction group) ZFS Intent Log (ZIL) RAIDZ Variable RAID stripe width Dynamic Stripping (add/subtract drives) All writes are full-stripe Portability - Filesystem transfer between SPARC and x86

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ZFS - Data checksum

Patterned off Merkle tree - each level of data to validate all things below it Similar to ECC memory Isolation of data and checksum

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ZFS - ZIL All system calls are logged as transaction records by

ZIL Records contain sufficient information to replay after crash Logs are variable size, depending on structure ZIL writes Small writes - data written as part of log Large writes - data written to disk and pointer to data written to log During mount time, ZFS checks for ZIL log - if exists, system probably crashed ZIL allows performance gains especially for databasesC O M P U T A T I O N A L R E S E A R C H D I V I S I O N

ZFS - RAIDZ Dynamic Stripe Width

Data and parity can be distributed across varying number of drives, depending on size All writes are full-stripe writes No need to read-modify-read RAID 5 penalty -read old data, corresponding parity, calculate new parity, and write new data and new parity

Dynamic Stripping

Data automatically redistributed as drives are subtracted and added Allows the usage for cheap disk for both data integrity, performance, and redundancy

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ZFS - Truths (no marketing) Not entirely new, but a software version of something

existing on hardware with some unique features RAIDZ - not really a RAID: RAID and filesystem are merged. (But this allows for usage of cheap drives) Jeff Bonwick - You have to traverse the filesystem metadata to determine the RAIDZ geometry Darcy - True RAID levels dont require knowledge of higher-level applications

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ZFS - Experimental Results Hardware - Ultra 2, with external RAID pack. Tested

UFS on Disksuite ZFS . What was tested? Performance: RAID 5 on Disksuite vs. RAIDZ Crash recovery Creating 400M files UFS on Disksuite RAID 5 (4 drives) Wed Jun 14 12:04:16 PDT 2006 Wed Jun 14 19:37:14 PDT 2006

ZFS RAIDZ (4 drives) Mon Jun 19 14:16:29 PDT 2006 Mon Jun 19 15:56:59 PDT 2006

Redundancy with removal of drive - simulate losing a drive

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Writer Performance: ZFS/UFS (Disksuite)

ZF :

ri e erformance 5 di ks

UF :

250000 200000

180000 200000 160000

140000 150000 200000-250000 kB/ 180000-200000 150000-200000 100000-150000 100000 50000-100000 0-50000 80000 50000 16384 2048 40000 64 60000 120000 kB/s 100000 160000-180000 140000-160000 120000-140000 100000-120000 80000-100000 60000-80000 40000-60000 20000-40000 0-20000 16384 4096 20000 0 64 128 64 256 512 1024 2048 4096 16 8192 16384 32768 65536 131072 262144 4 524288 1024 256 Record size kB 256 128 256 512 32 1024 2048 4096 8192 16384 32768 65536 131072 4 5