Использование функции smart, Инициализация виртуальных дисков, Фоновая инициализация – Инструкция по эксплуатации Dell PowerEdge RAID Controller 6i
Computer System Interface) см. на веб узле www.t10.org, а для интерфейса
SATA (Serial Attached ATA) — www.t13.org.
Инициализация виртуальных дисков
Инициализацию виртуальных дисков можно выполнить четырьмя
различными способами, которые будут описаны в следующих разделах.
Фоновая инициализация (BGI) — это автоматический процесс, который
пишет данные четности или зеркальные данные на вновь созданные
виртуальные диски. BGI предполагает, что данные на всех новых дисках
правильные. BGI не запускается на виртуальных дисках RAID 0.
Нельзя навсегда запретить BGI. При отмене BGI в течение
пяти минут автоматически производится перезагрузка. Чтобы получить
информацию об остановке BGI см. «Остановка фоновой инициализации» на
стр. 121.
2 creating storage configuration using ctrl-r – Avago Technologies MegaRAID SAS 9341-4i User Manual
disk media, so you risk losing the data in the disk cache if a power
failure occurs. The data is unrecoverable.
— IO Policy: The IO policy applies to read operations on a specific virtual drive. It does not affect the read-ahead
Direct: Read operations are not buffered in cache memory. Data is transferred to the cache and the host
concurrently. If the same data block is read again, it comes from cache memory. This setting is the default.
Cached: Read operations are buffered in cache memory before they are sent to the host.
— Drive Policy: Specify the drive cache policy.
Enable: Enable the drive cache.
Disable: Disable the drive cache.
NoChange: Leave the current drive cache policy as is. This setting is the default.
— Disable BGI: Specify the background initialization status.
No: Leave background initialization enabled. A new configuration can be initialized in the background while
you use WebBIOS to perform other configuration tasks. This setting is the default.
Yes: Select Yes if you do not want to allow background initialization for configurations on this controller.
— Select Size: Specify the size of the virtual drive or drives in MB, GB, or TB. Usually, this size is the full size for the
RAID 1 array shown in the Configuration panel on the right. You can specify a smaller size if you want to create
other virtual drives on the same drive group.
— Update Size: Click Update Size to update the Select Size Field value for the selected RAID levels.
16. Either click Accept to accept the changes to the virtual drive definition, or click Reclaim to return to the
17. Click Next after you define the virtual drives.
The Configuration Preview window appears.
18. Check the information in the configuration preview.
19. If the virtual drive configuration is acceptable, click Accept to save the configuration. Otherwise, click Back to
return to the previous screens and change the configuration.
20. If you accept the configuration, click Yes at the prompt to save the configuration and initialize the new
21. After the initialization is complete (the elapsed time depends on the RAID level and the disk size), click the Home
button, and then click Exit in the left hand window frame.
22. Select Exit Application, and reboot the computer with the Windows OS in the DVD drive or the CD drive.
Creating Storage Configuration Using Ctrl-R
Perform the following steps to create a virtual drive.
When the host computer is booting, hold down the Ctrl key and press the R key when the following text appears
on the window:
Copyright© Avago Technologies
Press <Ctrl><R> for Ctrl-R
The Controller Selection window appears.
In the VD Mgmt screen, navigate to the controller and press the F2 key.
The Create New VD screen appears.
Select a RAID 1level for the drive group from the RAID Level field.
Disable bgi raid что это
LSI MegaRaid настройка кеширования и системной производительности
Август 17th, 2017 
Evgeniy Kamenev
Установка и базовое использование утилиты megacli ддля работы с LSI MegaRaid описана в статье
https://kamaok.org.ua/?p=1896
В этой статье рассматриваются параметры кеширования чтения/записи, их настройка и влияния на производительность дисковой подсистемы ввода/вывода
Состояние RAID в том числе и значения политики кеширования можно получить следующей командой (отобразить все логические устройства всех контроллеров)
What do the «Cache Policy» values mean ?
are how the raid card uses on board RAM to collect data before writing out to disk or to read data before the system asks for it. Write cache is used when we have a lot of data to write and it is faster to write data sequentially to disk instead of writing small chunks. Read cache is used when the system has asked for some data and the raid card keeps the data in cache in case the system asks for the same data again. It is always faster to read and write to cache then to access spinning disks. Understand that you should only use caching if you have good UPS power to the system. If the system looses power and does not flush the cache it is possible to loose data. No one wants that. Lets look at each cache policy LSI raid card use.
uses the card’s cache to collect enough data to make a series of long sequential writes out to disk. This is the fastest write method.
tells the card to write all data directly to disk without cache. This method is quite slow by about 1/10 the speed of WriteBack, but is safer as no data can be lost that was in cache when the machine’s power fails.
uses an algorithm to see if when the OS asks for a bunch of data blocks sequentially, if we should read a few more sequential blocks because the OS _might_ ask for those too. This method can lead to good speed increases.
tells the raid card to only read the data off the raid disk if it was actually asked for. No more, no less.
allows the general use of the cards cache for any data which is read or written. Very efficient if the same data is accessed over and over again.
is straight access to the disk without ever storing data in the cache. This can be slow as any I/O has to touch the disk platters.
tells the card to use write caching even if the Battery Backup Unit (BBU) is bad, disabled or missing. This is a good setting if your raid card’s BBU charger is bad, if you do not want or can’t to replace the BBU or if you do not want WriteThrough enabled during a BBU relearn test.
if the BBU is not available for any reason then disable WriteBack and turn on WriteThrough. This option is safer for your data, but the raid card will switch to WriteThrough during a battery relearn cycle.
Use the hard drive’s own cache. For example if data is written out the drives this option lets the drives themselves cache data internally before writing data to its platters.
does not allow the drive to use any of its own internal cache.
What happens when the Battery Backup Unit (BBU) is bad, disabled or missing ?
The LSI raid BBU allows the raid controller to cache data before being written to the raid disks. Without the battery backup unit the raid card can not guarantee data in the card’s cache will be written to the physical disks if the power goes out. So, if the the BBU is bad, if the raid card is running a «battery relearn» test or if the BBU is disabled then the cached Write-Back policy is automatically disabled and Write-Through is enabled. The result of the direct to disk Write-Through policy is writes become an order of magnitude slower.
As a test we disabled cached Write-Back on our test raid. The bonnie++ benchmark test resulted in writes of 121MB/sec compared to enabling Write-Back and writing at 505MB/sec.
You can check the status of your BBU using the following command.
About This Document
This document describes the appearances and features of the redundant array of independent disks (RAID) controller cards, how to configure RAID arrays, and how to install drivers. The RAID controller cards include the LSI SAS2208, LSI SAS2308, LSI SAS3008IR, LSI SAS3008IT, LSI SAS3108, LSI SoftRAID, PM8060, and PM8068.
Intended Audience
This document is intended for:
- Technical support engineers
- Maintenance engineers
The server maintenance personnel must have adequate knowledge about the server products and service skills to avoid injury to human body or damage to devices during maintenance.
Symbol Conventions
The symbols that may be found in this document are defined as follows.
Symbol
Description
Indicates a hazard with a high level of risk which, if not avoided, will result in death or serious injury.
Indicates a hazard with a medium level of risk which, if not avoided, could result in death or serious injury.
Indicates a hazard with a low level of risk which, if not avoided, could result in minor or moderate injury.
Indicates a potentially hazardous situation which, if not avoided, could result in equipment damage, data loss, performance deterioration, or unanticipated results.
NOTICE is used to address practices not related to personal injury.
Supplements the important information in the main text.
NOTE is used to address information not related to personal injury, equipment damage, and environment deterioration.
Change History
Changes between document issues are cumulative. The latest document issue contains all changes made in previous issues.
Issue
Date
Description
- Modified section «Importing or Clearing a Foreign Configuration» for each RAID controller card.
- Changed the table remark format.
- Added the expandarray parameter and its description for RAID array capacity expansion.
- Optimized the LSI SAS3108 RAID controller card.
- Optimized the description of the drive strip size.
Added precautions for capacity expansion by adding drives.
Optimized the «Common Commands» section for each RAID controller card.
Optimized the description of parameters related to RAID array configuration.
Added the description about the Mini-SAS port on some RAID controller cards.
- Added the description of buzzer support to RAID controller cards.
- Added the description of the default strip size of each RAID controller card.
Added a new structure diagram to «Overview» section of LSI SAS3108 RAID controller card.