Quantum 3.1.4.1 manual

6-01376-15 Rev A StorNext ® 3.1.4.1 StorNext File System T uning Guide File System T uning Guide[...]

ii Quantum Product Name User’s Guide Document Title, 6-0137 6-15 Rev A, May 2010, Product of USA. Quantum Corporation provides this publication “as is” without warranty of any kin d, either express or implied, including but not limited to the i mplied warranties of merchantability or fitness for a particular purpose. Quantum Corporation may r[...]

StorNext File System Tuning Guide iii Contents The Underlying Storage System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 File Size Mix and Applicatio n I/O Characteristics . . . . . . . . . . . . . . . . . . 5 SNFS and Virus Checking . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 The Metadata Network .[...]

Contents iv StorNext File System Tuning Guide[...]

StorNext File System Tuning Guide 1 StorNext File System T uning The StorNext File Syste m (SNFS) provides ex tremely high per formance for widely varying scenarios. Many factors determine the level of performance you will realize. In particular , the performance characteristics of the underlying stor age system are the most critical factors. Howev[...]

StorNext File System Tuning The Underlying Storage System 2 StorNext File System Tuning Guide RAID Cache Configuration The single most important RAID tuning component is the cache configuration. This is pa rticular ly true for small I/O operations. Contemporary RAID systems such as the EMC CX series and the various Engenio systems provide excellent[...]

StorNext File System Tuning The Underlying Storage System StorNext File System Tuning Guide 3 operations involve a very high rate of small writes to the metadata disk, so disk latency is the critic al perf ormance factor . Write-bac k caching can be an effective approach to mini mizing I/O latency and optimi zing metadata operations throughput. Thi[...]

StorNext File System Tuning The Underlying Storage System 4 StorNext File System Tuning Guide While read-ahead caching improves sequential read performance, i t does not help highly tra nsactional performance. F urthermore, some SNFS customers actually observe maximu m large seque ntial read throughput by disabling caching. While disabling read-ahe[...]

StorNext File System Tuning File Size Mix and Application I/O Characteristics StorNext File System Tuning Guide 5 It can be useful to use a tool such as lmdd to help determine the storage system performance characteristic s and choose optimal settings. Fo r example, varying the stri pe size and running lmdd wit h a range of I/O sizes might be usefu[...]

StorNext File System Tuning File Size Mix and Applic ation I/O Characteristics 6 StorNext File System Tuning Guide and auto_dma_write_length , described i n the Mount Command Options on page 19 . Buffer Cache Reads and writes that aren't well-formed util ize the SNFS buffer cache. This also includes NFS or CIFS-based traff ic because the NFS a[...]

StorNext File System Tuning SNFS and Virus Checking StorNext File System Tuning Guide 7 If performance requirements canno t be achieved with NFS or CIFS, consider using a StorNext Distributed LAN client or fibre-chan nel attached client. It can be useful to use a tool such as netperf to help verify network performance characteristics. SNFS and Viru[...]

StorNext File System Tuning The Metadata Controller System 8 StorNext File System Tuning Guide ethtool too l can be very useful to investigate and adjus t speed/dupl ex settings. It can be useful to use a tool like netpe rf to help verify the Metadata Network performance characteristics. F or example, if netperf -t TCP_RR reports less than 15,000 t[...]

StorNext File System Tuning The Metadata Controller System StorNext File System Tuning Guide 9 used to realize performance gains from increased memory: BufferCacheSize , InodeCacheSize , and ThreadPoolSize . However , it is critical that the MDC system have enough physical memory available to ensure that the FSM process doesn’t get swapped out. O[...]

StorNext File System Tuning The Metadata Controller System 10 StorNext File System Tuning Guide StripeBreadth 256K MultiPathMethod Rotate Node CvfsDisk6 0 Node CvfsDisk7 1 [StripeGroup MetaFiles] Status UP MetaData Yes Journal No Exclusive Yes Read Enabled Write Enabled StripeBreadth 256K MultiPathMethod Rotate Node CvfsDisk0 0 [StripeGroup JournFi[...]

StorNext File System Tuning The Metadata Controller System StorNext File System Tuning Guide 11 Affinity AudFiles ##for Audio Fil es Only## Read Enabled Write Enabled StripeBreadth 1M MultiPathMethod Rotate Node CvfsDisk4 0 Node CvfsDisk5 1 Note: Affinity names cannot be lon ger than eight characters. StripeBreadth This setting must match the RAID [...]

StorNext File System Tuning The Metadata Controller System 12 StorNext File System Tuning Guide BufferCacheSize This setting consumes up to 2X bytes of memory times the number specified. Increasing this valu e can reduce latency of any metadata operation by performing a hot cache access to directory block s, inode information, and other metadata in[...]

StorNext File System Tuning The Metadata Controller System StorNext File System Tuning Guide 13 Example: ThreadPoolSize 32 # default 16, 512 KB memory per thread ForcestripeAlignment This setting should always be set to Y es. This is critical if the largest Str i pe Br e adt h defined is greater than 1MB. Note that this setting is not adjustable a [...]

StorNext File System Tuning The Metadata Controller System 14 StorNext File System Tuning Guide This setting is not adj ustable after initial file system creation, so i t is very important to give it careful consi deration during initi al configuration. Example: FsBlockSize 16K JournalSize The optimal settings for Jour nalSize are in the range betw[...]

StorNext File System Tuning The Metadata Controller System StorNext File System Tuning Guide 15 This setting is adjustabl e using the cvup datefs utility . For more information, see the cvup datefs man page. Example: JournalSize 16M SNFS T ools The snfsdefrag tool is very useful to iden tify and correct file extent fragmentation. Reducing extent fr[...]

StorNext File System Tuning The Metadata Controller System 16 StorNext File System Tuning Guide •L a r g e v a l u e f o r FSM threads SUMMAR Y max busy indicates the FSM configuration setting Threa dPoolSize is insufficient. • Extremely high values for FSM cache SUMMAR Y inode lookups , TKN SUMMAR Y T okenRequestV3 , or TKN SUMMARY T okenReqAl[...]

StorNext File System Tuning The Metadata Controller System StorNext File System Tuning Guide 17 The cvdbset utility has a special “Perf” trace flag that is very useful to analyze I/O performance. F or example: cvdbset perf Then, you can use cvdb -g to collect trace information such as this: PERF : Devi ce Write 41 MB/s IOs 2 exts 1 offs 0x 0 le[...]

StorNext File System Tuning The Metadata Controller System 18 StorNext File System Tuning Guide • Identify disk performance issues. If Device throughput is inconsistent or less than expected, it might indicate a slow disk in a stripe group, or that RAID tuning is necessary . • Identify file fragmentation. If the extent count “exts” is high,[...]

StorNext File System Tuning The Metadata Controller System StorNext File System Tuning Guide 19 slower CPU.) Differences in latency over time for the same system can indicate new hardware problems, such a s a network interface goin g bad. If a latency test has be en run for a particular cl ient, the cvadmin who long command includes the test resu l[...]

StorNext File System Tuning The Distributed LAN (Disk Proxy) Networks 20 StorNext File System Tuning Guide The dircachesize option sets the size of th e directory information cache on the client. This cache can dramatically improve the speed of readdir operations by reducing metadata network message traffic between the SNFS client and FSM. Increasi[...]

StorNext File System Tuning The Distributed LAN (Disk Proxy) Networks StorNext File System Tuning Guide 21 It is best practice to have all SN FS Distributed LAN clients and servers directly attached to the same ne twork switch. A router be tween a Distributed LAN client and server co uld be easily overwhelmed by the data rates required. It is criti[...]

StorNext File System Tuning The Distributed LAN (Disk Proxy) Networks 22 StorNext File System Tuning Guide Network Configuration and T opology Fo r maximum throughput, SNFS distributed LAN can utilize mult iple NICs on both clients and servers. In order to take advantage of this feature, each of the NICs on a given host must be on a di fferent IP s[...]

StorNext File System Tuning Distributed LAN Servers StorNext File System Tuning Guide 23 maximum of 1 GByte/s of throughput. SNFS automatically load- balances among NICs and se rvers to maximize throughput for all clients. Note: The diagram shows separate physic al switches used for the two subnetworks. They can, in fact, be the same swit ch, prov [...]

StorNext File System Tuning Distributed LAN Client Vs. Legacy Netwo rk Attached Storage 24 StorNext File System Tuning Guide •P e r f o r m a n c e •F a u l t T o l e r a n c e •L o a d B a l a n c i n g • Client Scalability • Robustness and Stability • Security Model Consistency Performance DLC outperforms NFS and CIFS for single-strea[...]

StorNext File System Tuning Windows Memory Requirements StorNext File System Tuning Guide 25 Robustness and Stability The code pat h for DLC is simp ler , invo lves fewer file system stacks, and is not integrated with ke rnel components th at constantly change with every operating system release ( for example, the Linux NFS code). Therefore, DLC pr[...]

StorNext File System Tuning Windows Memory Requirements 26 StorNext File System Tuning Guide being sent to the application log and cvlog.txt about socket failures with the status code (10555) which is ENOBUFS. The solution is to adjust a few parameters on the Cache Parameters tab in the SNFS control panel ( cvntclnt ). The se parameters control how[...]

StorNext File System Tuning Sample FSM Configuration F ile StorNext File System Tuning Guide 27 Sample FSM Configuration File This sample configuration f ile is lo cated in the SNFS in stall directo ry under the exampl es subdirectory name d example.cfg. # ************************************ ************************ # A global section for definin [...]

StorNext File System Tuning Sample FSM Configuration File 28 StorNext File System Tuning Guide # StripeAlignSize 2M # auto alignment, default MAX(StripeBreadth) # OpHangLimitSecs 300 # default 180 secs # DataMigrationThreadPoolSize 128 # Managed only, default 8 # ************************************ ************************ # A disktype section for[...]

StorNext File System Tuning Sample FSM Configuration F ile StorNext File System Tuning Guide 29 [Disk CvfsDisk3] Status UP Type VideoDrive [Disk CvfsDisk4] Status UP Type VideoDrive [Disk CvfsDisk5] Status UP Type VideoDrive [Disk CvfsDisk6] Status UP Type VideoDrive [Disk CvfsDisk7] Status UP Type VideoDrive [Disk CvfsDisk8] Status UP Type VideoDr[...]

StorNext File System Tuning Sample FSM Configuration File 30 StorNext File System Tuning Guide [Disk CvfsDisk15] Status UP Type DataDrive [Disk CvfsDisk16] Status UP Type DataDrive [Disk CvfsDisk17] Status UP Type DataDrive # ************************************ ************************ # A stripe section for defining stri pe groups. #*************[...]

StorNext File System Tuning Sample FSM Configuration F ile StorNext File System Tuning Guide 31 Node CvfsDisk3 1 Node CvfsDisk4 2 Node CvfsDisk5 3 Node CvfsDisk6 4 Node CvfsDisk7 5 Node CvfsDisk8 6 Node CvfsDisk9 7 [StripeGroup AudioFiles] Status UP Exclusive Yes##Exclusive StripeGroup for Audio File Only## Affinity AudFiles Read Enabled Write Enab[...]

StorNext File System Tuning Sample FSM Configuration File 32 StorNext File System Tuning Guide[...]