Dell PowerVault MD3000i Dell PowerVault MD3000/MD3000i Array Tuning Best Pract
Dell PowerVault MD3000i Manual
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- Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 1
POWERVAULT MD3000 AND MD3000i ARRAY TUNING BEST PRACTICES dell.com/PowerVault - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 2
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices DISCLAIMER THIS WHITE PAPER IS FOR INFORMATIONAL PURPOSES ONLY, AND MAY CONTAIN TYPOGRAPHICAL ERRORS AND TECHNICAL INACCURACIES. THE CONTENT IS PROVIDED AS - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 3
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices Table of Contents 1 AUDIENCE AND SCOPE ...4 2 PERFORMANCE TUNING OVERVIEW ...4 2.1 COMPONENTS THAT INFLUENCE STORAGE PERFORMANCE 4 2.2 BASIC APPROACH TO PERFORMANCE TUNING ...4 3 APPLICATION SOFTWARE CONSIDERATIONS 5 4 CONFIGURING THE - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 4
.XX) storage array. For further detail on determining Firmware Generation of a MD3000 or MD3000i storage array, please view the Dell™ Users Guide at http://support.dell.com/manuals. 2 Performance Tuning Overview The challenge of storage performance tuning is to understand and control the interacting - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 5
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices The answers include: • "It depends..." There are no absolute answers. Each environment is unique and the correct settings depend on the unique goals, configuration, and demands for the specific environment. • "Actual mileage may vary." - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 6
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices • Profile of mean I/O direction; this is usually the ratio of Reads to Writes 4 Configuring the MD3000/MD3000i There are two ways to configure the MD3000 and MD3000i storage systems. The most common and easiest method is using the MDSM. - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 7
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices Physical disk cost is not the only factor that influences the decision on which RAID level is most appropriate for a given application. The performance of a chosen RAID where cache memory and RAID Controller Modules are not overly - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 8
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices 4.1.1 Selecting a RAID Level - High Write Mix Scenario In random I/O applications with a >10% mix of write operations and a low degree of burstiness, RAID 1/10 provides the best overall performance for redundant disk groups. RAID 1/10 - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 9
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices • To optimize for data transfer rate of drives that matches the per virtual disk group I/O rate needed to support the application. Make sure to account for the I/Os required to implement the data protection of the selected RAID level. - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 10
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices traffic virtual disks share a disk group, even with purely sequential usage models, the disk group I/O behavior becomes increasingly random, lowering overall performance. - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 11
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices first 128KiB of an I/O is written to the first drive, the next 128KiB to the next drive, and so on with a total stripe size of 512KiB. For a RAID 1, 2 + 2 virtual disk group, 128KiB would be written to each of the two drives (and same - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 12
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices 4.6 Cache Settings Read-ahead cache can be configured in the MDSM and through the CLI. The MDSM has only the defaults to work with, while the CLI can fully configure the read-ahead cache. Additionally, the global cache block size for - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 13
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices 4.6.3 Setting the Storage Array Cache Block Size Configured through the CLI - This command is available at the storage array level and effects all virtual disks and disk-groups. Cache Block Size - Cache Block Size refers to the way - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 14
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices 4.7 Tuning Using Array Performance Data 4.7.1 Collecting Performance Statistics The stateCaptureData.txt and performanceStatistics.csv files, which are available through the MDSM, Support tab as part of a Technical Support Bundle, - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 15
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices Figure 2: First Generation Firmware - RAID Level. File: stateCaptureData.txt Virtual Disk Unit 0 Configuration Volume Type: 13+1 RAID 5 User Label: MyRAID5_1 Block Size: 512 bytes Large IO: 4096 blocks Segment Size: 256 - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 16
Dell™ PowerVault MD3000 and MD3000i Array when tuning the storage. The data Firmware - Performance Statistics Broken Out. File: stateCaptureData.txt *** Performance stats *** Cluster be sized as even powers of two. The average RAID level's benefit from careful tuning of stripe and segment size, RAID - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 17
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices In the first generation of firmware (see Figure 5), this can be determined 5: First Generation Firmware - Stripe Size. File: stateCaptureData.txt Virtual Disk Unit 0 Configuration Volume Type: 13+1 RAID 5 User Label: MyRAID5_1 - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 18
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices In addition, the stateCaptureData.txt file provides Figure 7: First Generation Firmware- Stripe distribution. File: stateCaptureData.txt Virtual Disk Unit 0 Configuration Volume Type: 13+1 RAID 5 User Label: MyRAID5_1 Block Size: - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 19
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices Figure 8: Second Generation Firmware- Stripe distribution. File: stateCaptureData.txt Volume 0 Attributes: Volume Type: RAIDVolume User 100.33% Cluster Reads Cluster Writes Stripe modified and written. In RAID level 5 and 6 this - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 20
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices RMW, or Read-Modify-Write, is the second-best write algorithm available for RAID 5 and 6. A RMW occurs when a quantity of bits, smaller or equal to an individual segment are modified. This constitutes a two-read operation in RAID 5 and - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 21
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices Figure 10: Second Generation Firmware - Write Algorithms Volume 1 Attributes: Volume Type: RAIDVolume User Label: MyRAID5vd ... BlockSize: 512 bytes LargeIoSize: 4096 blocks ... Perf. Stats: Requests Blocks Reads - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 22
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices For a complete list of commands and instructions on using the CLI Performance Monitor, refer to the Dell™ PowerVault™ Modular Disk Storage Manager CLI Guide on http://support.dell.com/manuals. 4.9 Other Array Considerations 4.9.1 Global - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 23
when sharing bandwidth on MD3000i with multiple NICs. • Give each NIC its own IP address. • Connect each NIC to a separate switch, or direct attach host NIC(s) to target iSCSI port(s). • Use separate NICs for public network access than the storage array iSCSI session. Install additional NICs as - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 24
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices Figure 11: MD3000i Advanced IPv4 Settings: VLAN, QOS, Jumbo Frames Support 5.1.3 Sharing Bandwidth with Multiple SAS HBAs Each SAS wide port includes four full duplex serial links within a single connector. The individual SAS 1.1 - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 25
Dell™ PowerVault MD3000 and MD3000i Array Tuning storage system is kept busy with a steady supply of I/O requests from the host application. Become familiar with the parameters that the operating system provides for controlling I/O, such as maximum transfer size. 5.2.2 Aligning Host I/O with RAID - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 26
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices Microsoft provides the diskpar.exe utility as part of the Microsoft Windows 2000 Resource Kit, which was renamed to diskpart.exe in Microsoft Windows 2003 and later. Microsoft has a KB article 929491 covering this, and Dell™ always - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 27
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices Appendix A: Obtaining Additional Performance Tools Table and characterization tool File system benchmark tool Tool for measuring and characterizing drive subsystem I/O Windows, Unix/Linux Windows, Unix/Linux Windows, Unix/Linux - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 28
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices Appendix B: System Troubleshooting For information about troubleshooting MD3000 and MD3000i storage arrays, refer to the "Troubleshooting Problems" chapter of the Dell™ PowerVault™ Modular Disk Storage Manager User's Guide. Go to: - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 29
en/index.htm PowerVault MD3000i SAN Array for Storage Consolidation, http://www.dell.com/content/products/productdetails.aspx/pvaul_md3000i? c=us&1=en&s=bsd&cs=04 Using iSCSI: Dell™ PowerValut™ Modular Disk Storage Manager User's Guide, http://support.dell.com/support/edocs/systems/md3000/en/UG/HTML - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 30
with SAS front-end. Dell™ PowerVault MD3000i Expandable Storage Array with iSCSI front-end. Dell™ Modular Disk Storage Manager. Host management utility suite for configuring and maintaining a MD3000/MD3000i storage array. Mebibyte, see kibibyte. Network Interface Controller Near-line SAS; A hybrid - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 31
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices Term RAID RAID 0 RAID 1/10 RAID 5 RAID 6 RPA Definition directly on the drive in lieu of using an SATA interposer. Redundant Array of Inexpensive Disks RAID Level 0; RAID 0 is a striped set with no redundant information. It is - Dell PowerVault MD3000i | Dell PowerVault MD3000/MD3000i Array Tuning Best Pract - Page 32
Dell™ PowerVault MD3000 and MD3000i Array Tuning Best Practices Term Segment Short I/O SQL Stripe Definition by t10.org A segment is the data written to one drive in a virtual disk group stripe before writing data to the next drive in the virtual disk group stripe. Any I/O that consumes less that
ARRAY TUNING
BEST PRACTICES
dell.com/PowerVault
POWERVAULT
MD3000 AND
MD3000i