Quantum 3.5.2 manuale d’uso

6-01376-14 StorNext 3.5.2 ® StorNext File System T uning Guide File System T uning Guide File System T uning Guide[...]

StorNext 3.5.2 File Syst em Tuning Guide, 6-01376-14 , Ver. A, Rel. 3.5.2 , February 2010, Made in USA. Quantum Corporation provides this publ ication “as is” without warranty of an y kind, either express or implied, including but not limited to the implied warranties of merc hantability or fitness for a particular purpose. Quantum Corporation [...]

StorNext File System Tuning Gu ide i Content s Chapter 0 StorNext File System Tuning 1 The Underlying Storage System ............. ... ......... .............. .............. .............. ... 1 RAID Cache Configuration .............. .............. .............. ............... .............. 2 RAID Write-Back Caching .... .............. .......[...]

StorNext File System Tuning Guide 1 0 S torNext File System T uning The StorNext File System (SNFS) pr ovides extremely high performance for widely varying scenarios. Many factors determine the level of performance you will realiz e. In particular, the performance characteristics of the underlying st orage system are the most critical factors. Howe[...]

StorNext File System T uning The Underlying Storage System StorNext File System Tuning Guide 2 RAID Cache Configuration 0 The single most i mportant RAID tuning component is the cache configuration. This is particular ly t rue for small I/O operat ions. Contemporary RAID systems such as the EMC CX series and the various Engenio systems provide exce[...]

StorNext File System T uning 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 critical perf ormance factor. Write-back caching can be an effective approach to mini mizing I/O latency and optimizing metadata operations throughput. This i[...]

StorNext File System T uning The Underlying Storage System StorNext File System Tuning Guide 4 While read-ahead caching improves sequ ential read performance, it does not help highly transactional perf ormance. Furthermore, some SNFS customers actually observe maximum large sequential read throughput by disabling caching . While disabling read-ahea[...]

StorNext File System T uning File Size Mix and Application I/O Characteristics StorNext File System Tuning Guide 5 example, varying the stripe size an d running lmdd with a range of I/O sizes might be useful to determine an optimal stripe size multiple to configure the SNFS StripeBreadth . Some storage vendors now provide RAID6 capability for impro[...]

StorNext File System T uning File Size Mix and Application I/O Characteristics StorNext File System Tuning Guide 6 Buffer Cache 0 Reads and writes that aren't well-for med utilize the SNFS buffer cache. This also includes NFS or CIFS -bas ed traffic because the NFS and CIFS daemons defeat well-formed I/Os issued by the application. There are s[...]

StorNext File System T uning SNFS and Virus Checking StorNext File System Tuning Guide 7 It can be useful to use a tool such as netperf to help verify network performance characteristics. SNFS and V irus Checking Virus-ch ecking so ftware can se vere ly degrade the performance of any file system, including SNFS . If you ha ve anti-virus software ru[...]

StorNext File System T uning The Metadata Controller System StorNext File System Tuning Guide 8 It can be useful to use a tool like netperf to help verify the Metadata Network performance characte ristics. For example, if netperf -t TCP_RR reports less than 15,000 transactions per second capacity, a performance penalty may be incurred. You can also[...]

StorNext File System T uning The Metadata Controller System StorNext File System Tuning Guide 9 However, it is critical that the MDC system have e nough physical memory available to ensure that the FSM process do esn’t get swap ped out. Otherwise, severe performance degradation and syst em instability can result. The operating system on the metad[...]

StorNext File System T uning The Metadata Controller System StorNext File System Tuning Guide 10 MultiPathMethod Rotate Node CvfsDisk6 0 Node CvfsDisk7 1 [S tripeGroup MetaFiles] S tatus UP Meta D ata Y es Journal No Exclusive Y es Read Enabled Wr it e Enabled S trip eBreadth 256K MultiPathMethod Rotate Node CvfsDisk0 0 [S tripeGroup JournFiles] S [...]

StorNext File System T uning The Metadata Controller System StorNext File System Tuning Guide 11 For optimal performance, files that are accessed using large D MA-based I/O could be steered to wide-strip e stripe groups. Less performance- critical file s could be steered to slow disk stripe groups. Small files could be steered to narrow-st ripe str[...]

StorNext File System T uning The Metadata Controller System StorNext File System Tuning Guide 12 Example: [stripeGroup VideoFiles] S tatus UP Exclusive Y es ##These T wo lines set Exclusive stripeGroup# # Affinity V idFiles ##for Video Files Only## Read Enabled Wr it e Enabled S tripeBreadth 4M MultiPathMethod Rotate Node CvfsDisk2 0 Node CvfsDisk3[...]

StorNext File System T uning The Metadata Controller System StorNext File System Tuning Guide 13 ThreadPoolSize 0 This setting consumes u p to 512 KB memory times the number specified. Increasing this value can improve c oncurrency of metadata operations. For example, if many client proces ses are executing concurrently, the thread pool can become [...]

StorNext File System T uning The Metadata Controller System StorNext File System Tuning Guide 14 For metadata disk size, you must have a minimum of 25 G B, with more space allocated depending on the numb er of files per directory and the size of your fi le system. The following t able shows suggested FsBlockSize (FSB) s ettings an d metadata disk s[...]

StorNext File System T uning The Metadata Controller System StorNext File System Tuning Guide 15 JournalSize 0 The optimal settings for JournalSize are in the range between 16M and 64M, depending on the FsBlockSize . Avoid val ues greater than 64M due to potentially severe impacts on startu p and failover times. Values at the higher end of the 16M-[...]

StorNext File System T uning The Metadata Controller System StorNext File System Tuning Guide 16 The following items are a few things to watch out for: • A non-zero value for FSM wait SUMMAR Y journal waits indicates insufficient IOPS performance of th e disks assigned to the metadata stripe group. This usually req uires reducing the metadata I/O[...]

StorNext File System T uning The Metadata Controller System StorNext File System Tuning Guide 17 preallocation and stripe alignment. In the directory-to-directory copy mode (for example, cvcp source_dir destination _dir ,) cvcp conditionally uses the Bulk Create API to provide a dramatic small file copy performance boost. However, it will not use B[...]

StorNext File System T uning The Metadata Controller System StorNext File System Tuning Guide 18 Sample use cases: • Verify that I/O properties are as expe cted. You can use the VFS trace to ensure th at the displayed properties are consistent with expectations, such as being well formed; buffered versus DMA; shared/non-shared; or I/O size. If a [...]

StorNext File System T uning The Metadata Controller System StorNext File System Tuning Guide 19 displayed by the cvadmin who command). If all is specified, the test is run against each client in turn. The test is run for 2 seconds, unle ss a value for seconds is specified. Here is a sample run: snadmin (lsi) > latency-test T est started on clie[...]

StorNext File System T uning The Distributed LAN (Disk Proxy) Networks StorNext File System Tuning Guide 20 background for improved performance. The default setting is optimal in most scenarios. The auto_dma_ read_length and auto_dma_wri te_length settings determine the minimum transfer size where di rect DMA I/O is performed instead of using the b[...]

StorNext File System T uning The Distributed LAN (Disk Proxy) Networks StorNext File System Tuning Guide 21 anticipated traffic between all Di stributed LAN clients and servers connected to them. A network switch that is dropping pack ets will cause TCP retransmissions. This can be easily observed on both Linux and Windows platforms by using the ne[...]

StorNext File System T uning The Distributed LAN (Disk Proxy) Networks StorNext File System Tuning Guide 22 It can be useful to use a tool like netperf to help verify the performance characteristics of each Distri buted LAN network. (When using netperf , on a system with mu ltiple NICs, take care to specify the right IP addresses in order to ensure[...]

StorNext File System T uning Distributed LAN Servers StorNext File System Tuning Guide 23 In the diagram there are two subnetwork s: the blue subnetwork (10.0.0.x) and the red subnetwork (192.168.9.x). Se rvers such as S1 are connecte d to both the blue and red subnetwork s, and can each provide up to 2 GByte/s of throughput to clients. (The three [...]

StorNext File System T uning Distributed LAN Client Vs. Legacy Network Attached Storage StorNext File System Tuning Guide 24 Distributed LAN Client Vs. Legacy Network Attached S torage 0 StorNext provides support for lega cy Network Attached Storage (NAS) protocols, including Network File Sys tem (NFS) and Common Interne t File System (CIFS). Howev[...]

StorNext File System T uning Distributed LAN Client Vs. Legacy Network Attached Storage StorNext File System Tuning Guide 25 Load Balancing 0 DLC automatically ma kes use of all available Dist ributed LAN Servers in an active/active fashion, and evenly spreads I/O across them. If a serv er goes down or one is added, the load balancing system automa[...]

StorNext File System T uning Windows Memory Requirements StorNext File System Tuning Guide 26 Windows Memory Requirements Beginning in version 2.6.1, StorNext includes a number of performance enhancements that enable it to bette r react to changing customer load. However, these enhancements come with a price: memory requirement. When running on a 3[...]

StorNext File System T uning Windows Memory Requirements StorNext File System Tuning Guide 27 The more cvnodes that there are encached on the client, the fewer trips the client has to make over the wire to contact the FSM. Each cvnode is approximately 1462 bytes in size and is allocated from the non-paged pool. The cvnode cache is periodically purg[...]

StorNext File System T uning Sample FSM Configuration File StorNext File System Tuning Guide 28 Sample FSM Configuration File This sample configuration file is locat ed in the SNFS install directory under the examples subdirectory named example.cfg. # ****************** *************** *** *************** **** ****************** # A global section [...]

StorNext File System T uning Sample FSM Configuration File StorNext File System Tuning Guide 29 # # ThreadP oolSize 64 # defaul t 16, 2 MB m emory per thre ad # InodeCacheSize 32K # 800-1000 bytes each, default 32K # BufferCacheSize 64M # default 32MB # S tripeAlignSize 2M # auto alignment, default MAX(S tripeBreadth) # OpHangLimitSecs 300 # defaul[...]

StorNext File System T uning Sample FSM Configuration File StorNext File System Tuning Guide 30 ****************** ************** ******************* ****************** **** [Disk CvfsDisk0] S tatus UP T ype MetaDrive [Disk CvfsDisk1] S tatus UP T ype Jou rnalDrive [Disk CvfsDisk2] S tatus UP T ype VideoDrive [Disk CvfsDisk3] S tatus UP T ype Video[...]

StorNext File System T uning Sample FSM Configuration File StorNext File System Tuning Guide 31 [Disk CvfsDisk8] S tatus UP T ype VideoDrive [Disk CvfsDisk9] S tatus UP T ype VideoDrive [Disk CvfsDisk10] S tatus UP T ype Aud ioDrive [Disk CvfsDisk1 1] S tatus UP T ype Aud ioDrive [Disk CvfsDisk12] S tatus UP T ype Aud ioDrive [Disk CvfsDisk13] S ta[...]

StorNext File System T uning Sample FSM Configuration File StorNext File System Tuning Guide 32 S tatus UP T ype Da taDrive [Disk CvfsDisk17] S tatus UP T ype Da taDrive # ****************** *************** *** *************** **** ****************** # A stripe section for defining stripe groups. # ****************** *************** *** ***********[...]

StorNext File System T uning Sample FSM Configuration File StorNext File System Tuning Guide 33 S tatus UP Exclusive Y es##Exclusive StripeGroup for V ideo Files Only## Affinity VidFiles Read Enabled Wr it e Enabled S tripeBreadth 4M MultiPathMethod Rotate Node CvfsDisk2 0 Node CvfsDisk3 1 Node CvfsDisk4 2 Node CvfsDisk5 3 Node CvfsDisk6 4 Node Cvf[...]

StorNext File System T uning Sample FSM Configuration File StorNext File System Tuning Guide 34 Wr it e Enabled S trip eBreadth 256K MultiPathMethod Rotate Node CvfsDisk14 0 Node CvfsDisk15 1 Node CvfsDisk16 2 Node CvfsDisk17 3[...]