- ページ 12
ストレージ Dell PowerVault MD3000iのPDF チューニング・マニュアルをオンラインで閲覧またはダウンロードできます。Dell PowerVault MD3000i 32 ページ。 Configuration for vmware esx server software
Dell PowerVault MD3000i にも： サポートノート (22 ページ), アップグレードマニュアル (28 ページ), ユーザーマニュアル (46 ページ), 交換マニュアル (4 ページ), 設定マニュアル (10 ページ)
ページを印刷する
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 read and write
cache can be adjusted through the CLI.
Please refer to the Dell™ PowerVault™ Modular Disk Storage Manager CLI
Guide on the Dell™ technical support site (http://support.dell.com/manuals) for a
complete list of supported commands including the following cache specific
commands.
4.6.1 Setting the Virtual Disk-Specific Write Cache and Write Cache Mirroring
Configured through the CLI – These commands are available at the virtual disk
level.
Write Cache – Disabling write cache puts the controllers into a write-through
mode, adding additional latency while data is flushed to the disk. Except for
specific read-only environments, it is recommended that this setting stay
enabled. Write cache is automatically disabled in the case of cache battery
failure or a cache battery learn cycle.
Write Cache Mirroring – Write Cache Mirroring provides an additional level of
redundancy and fault tolerance in the MD3000 and MD3000i. As a side effect, it
reduces available physical memory and intra-controller bandwidth to perform this
operation. In select, non data-critical cases, it can be beneficial to adjust this
parameter. For normal use, Dell™ always recommends Enabling Cache
Mirroring. Cache Mirroring is automatically disabled in the event of controller
failure or when write caching is disabled.
WARNING: Data loss can occur if a RAID controller module fails while write-
caching without cache mirroring is enabled on a virtual disk.
4.6.2 Setting the Virtual Disk-Specific Read Cache Pre-fetch
Configured through the CLI – This command is available at the virtual disk level.
Read Cache Pre-fetch – The Read Cache setting can be toggled on a virtual disk
level. Disabling read pre-fetch is primarily useful in primarily small transfer size
random read environments, where pre-fetch of random data would not provide
sufficient value. However, the normal observed overhead of read pre-fetch is
negligible. For most environments, Dell™ always recommends Enabling Read
Pre-fetch.
December 2008 – Revision A01
Page 12