InfoScale™ 9.0 SmartIO for Solid-State Drives Solutions Guide - Linux

Last Published:
Product(s): InfoScale & Storage Foundation (9.0)
Platform: Linux
  1. Introducing SFHA Solutions SmartIO
    1.  
      About SmartIO for solid-state drives
    2.  
      About SmartIO in an SFHA environment
    3.  
      About SmartIO in an Active/Active cluster environment
    4.  
      About SmartIO in the Solaris virtualized environments
    5.  
      About SmartIO in the Linux virtualized environment
    6.  
      About the SmartIO caching profiler tool
  2. Using the SmartIO feature: use cases
    1. About SmartIO read caching for applications running on VxVM volumes
      1.  
        Required configuration for SmartIO read caching for VxVM volumes
      2.  
        Automatic caching for VxVM volumes
      3.  
        Setting up SmartIO read caching for VxVM volumes
      4.  
        Verifying the VxVM cache area and monitoring the caching
    2. About SmartIO read caching for applications running on VxFS file systems
      1.  
        Required configuration for SmartIO read caching for a VxFS file system
      2.  
        Automatic caching for VxFS file systems
      3.  
        Setting up SmartIO read caching for VxFS file systems
      4.  
        Verifying the VxFS cache area and monitoring the caching
      5.  
        Customizing the caching behavior
    3. About SmartIO caching on SSD devices exported by FSS
      1.  
        Status of cache areas when nodes leave or join the cluster
      2.  
        Setting up cache areas using SSDs exported by FSS
    4. About SmartIO write-back caching for applications running on VxFS file systems- DLV 11 to 13
      1.  
        Required configuration for SmartIO write-back caching for a VxFS file system
      2.  
        Setting up SmartIO write-back caching for VxFS file systems
      3.  
        Verifying the VxFS cache area and monitoring the caching (writeback mode)
    5. About SmartIO FEL-based writeback caching for applications running on VxFS file systems- DLV 14 and later
      1.  
        Required configuration for FEL-based write-back caching for a VxFS file system
      2.  
        Setting up FEL-based write-back caching for VxFS file systems
      3.  
        Verifying the VxFS cache area and monitoring FEL-based write-back caching
    6. About multiple SmartIO cache areas for read and write-back caching on VxFS file systems
      1.  
        About the smartiocache option
      2.  
        Converting VxFS cache areas from one type to another
      3.  
        Setting up multiple cache areas on a system
      4.  
        Verifying the VxFS cache areas
    7. About SmartIO caching for Oracle databases on VxFS file systems
      1.  
        Prerequisites and configuration for using the SmartIO plug-in for Oracle
      2.  
        Setting default SmartIO caching policies for a database running on a VxFS file system
      3.  
        Setting SmartIO caching policies for database objects
      4.  
        Pinning and unpinning database objects
      5.  
        Enabling and disabling caching for the database
      6.  
        Listing cache policy details for the database
      7.  
        Listing cache statistics for the database
    8. About SmartIO caching for databases on VxVM volumes
      1.  
        Applying a SmartIO database caching template for a VxVM volume
    9.  
      Technology Preview: Distributed SmartIO in Arctera InfoScale storage environments
  3. Administering SmartIO
    1.  
      Creating a cache area
    2.  
      Displaying information about a cache area
    3. Enabling or disabling caching for a data object
      1.  
        Enabling or disabling caching for a file system
      2.  
        Enabling or disabling caching for a data volume
    4.  
      Adding a device to the cache area
    5.  
      Pausing caching from a volume to a cache area
    6.  
      Removing a device from the cache area
    7.  
      Destroying a cache area
    8.  
      Setting the attributes of the VxVM cache area
    9.  
      Setting or changing the caching mode for a VxFS cache area
    10.  
      Flushing dirty data from a writeback cache area
    11.  
      Tuning the writeback caching
    12. Viewing the SmartIO cache statistics
      1.  
        Viewing the detailed caching stats for a VxVM cache area
      2.  
        Viewing the detailed caching stats for a VxFS cache area
  4. Troubleshooting and error handling
    1. Support for a persistent or 'warm' VxVM cache
      1.  
        Primary volume failure with a stale cache could cause possible data corruption
      2.  
        Migrating a cache during HA failover is not supported
    2.  
      Cache area is lost after a disk failure (3158482)
    3.  
      Cache is not online after a reboot
    4.  
      Recovering the write-back cache after a node failure
  5. Appendix A. Command reference
    1.  
      SmartIO command reference

Viewing the SmartIO cache statistics

Use the sfcache stat command to display the cache statistics for the system.

Table: Cache statistics describes the cache statistics in the output.

Table: Cache statistics

Field

Description

HIT RATIO (VxVM cache)

Percentage of total I/Os that are satisfied from the cache. Displayed for reads and writes.

ART(Hit)ms (VxVM cache)

Average response time for I/Os that are satisfied from the cache.Displayed for reads (RD) and writes (WR).

ART(Miss)ms (VxVM cache)

Average response time for I/Os that are not satisfied from the cache. Displayed for r reads (RD) and writes (WR) .

BYTES (VxVM cache)

Total size of I/Os for reads (RD) and writes (WR).

NAME (VxVM cache)

Name of the cache area.

TYPE (VxVM cache)

Whether the cache area is VxVM or VxFS.

%CACHE (VxVM cache)

Percentage of the cache area that is currently used for data.for all data objects.

Cache Size (VxFS cache)

Size of the cache area.

Cache Utilization (VxFS cache)

Percentage of the cache area that is currently used for data.

File Systems Using Cache (VxFS cache)

Number of file systems using the cache.

Writeback Cache Use Limit (VxFS cache)

Size of the cache area that is used for writeback.

You can set the size with the writeback_size attribute. If no size is set, the field displays Unlimited.

See Tuning the writeback caching.

Writeback Flush Timelag

Interval between when the data is written to the cache and when it is flushed to the disk. If the Writeback Flush Timelag is small, such as 10 seconds, then sfcache statistics will not show. Data is flushed to disk faster. In this case, you can determine the caching usage based on the WB Hit Ratio.

Hit Ratio (VxFS cache)

Percentage of total I/Os that are satisfied from the cache. Displayed for reads and writes.

Data Read (VxFS cache)

Data read from the cache.

Data Written (VxFS cache)

Data written to the cache.

Files Cached (VxFS cache)

Number of files present in the cache.

Files Pinned (VxFS cache)

Number of pinned files in the cache.

Data Pinned (VxFS cache)

Amount of data pinned in the cache.

To view the cache statistics

  • Use the following command:
    # sfcache stat
                           HIT RATIO   ART(Hit)ms  ART(Miss)ms   BYTES
NAME            %CACHE RD    WR    RD    WR    RD    WR    RD     WR
TYPE: VxVM
sfcachearea_1   13.43  91.24 94.20 0.142 0.819 0.414 0.798 15.31g 4.21g

TYPE: VxFS
NAME: sfcachearea_2
               Cache Size:    48.0 GB
        Cache Utilization:    72.2 MB ( 0.15 %)
 File Systems Using Cache:       1
Writeback Cache Use Limit:  Unlimited
  Writeback Flush Timelag:      10 s

Read Cache
Hit Ratio  Data Read  Data Written  Files Cached  Files Pinned  Data Pinned
   0.00 %       0 KB          0 KB             0             0         0 KB