>>Q: WebBIOS中的DiskActivity屬性是做啥用的?
>>A: 作為定位disk之用(locate a disk). Use disk activity for locate...
>>Q: 為啥SATA SSD/HDD在Green Activity LED沒有恆亮?
>>A: LSI=> The expected behavior is a continuously lit green LED when a drive is online, optimal, and not running I/O. I expect that there may be some difference in the way the backplane is addressing the SATA drives.
>>>> Supermicro=> HDD activity LED is controlled by HDD, and its behavior is determined by its microcode.
SAS and SATA HDD will have different behavior, it is normal.
In normal state:
SAS HDD – activity LED on( green )
SATA HDD – activity LED off
>>Q: 增強型的Dimmer Switch在SATA和SAS間有沒有差異?
>>A: 有. SAS和SATA有不同的電源管理規格. SAS的優勢性更高. T10 Power State....
2011/01/18
>>Q: 6Gb/s HDD/SSD為什麼安裝在3Gb/s MegaRAID SAS Controller, 發現Negoiation Link Speed會強制在1.5Gb/s的速率呢?
>>A: LSI=> 3Gb/s MegaRAID controllers were designed before the 6Gb/s standard was developed. The card may not automatically set the correct link rate for 6Gb/s products. We cannot guarantee that the 3Gb/s speed will automatically be negotiated to with 6Gb/s drives connected to the 3Gb/s controller.
2011/02/03
>>Q: MegaCLI中的LDBBM是指甚麼呢? 他有甚麼用處? 如何作用?
>>A: 他指的是Logical Drive Battery Back-up Module, 指的就是BBU部分.作用方式, 根據LSI的說法如下:
If your controller supports BBUs, you are using a BBU, and you are write caching, the flag should change.
>>Q: PFK是指甚麼? 作甚麼用?
>>A: PFK就是Premium Features Key. 透過PFK可以用來啟動LSI的高階軟體服務來加值. 根據LSI的說法:
There are two types of advanced software keys: hardware and license. If you purchase a hardware key, seating the key on the board will flip a switch in the NVRAM. Removing the hardware key will change that switch back to its original state. In essence, the key is not a permanent change. In other words, you cannot purchase a hardware key, seat it on several boards, and permanently enable the feature.
License keys are permanent switches, but they are single-use. Enabling the license will make a change in the NVRAM which is permanent, but the license is automatically disabled after first use.
>>Q: MegaCLI的PFK in NVRAM是指甚麼呢?
>>A: 就是在NVSRAM存放PFK. 根據LSI的說法如下:
License keys are permanent switches, but they are single-use. Enabling the license will make a change in the NVRAM which is permanent, but the license is automatically disabled after first use.
>>Q: 這樣做有何目的?
>>A: LSI=> The goal is to prevent duplication of single licenses.
>>Q: 軟體認證依然具備遷移性(Migration)嗎?
>>A: LSI=> Yes, you can remove it from one and move it to another. It will no longer work on the old controller, but it will work on the new controller.
>>Q: TLER/ERC/CCTL會不會跟SMART Polling有關係呢?..
>>A: 多多少少有些關係, 但是不是SMART Polling跟TLER/ERC/CCTL成絕對關係.
SMART polling and TLER are only related in the sense that both deal with disk errors. The controller does SMART poll, but this is not related to TLER.
TLER/ERC/CCTL的設計就是防範當error correction超過RAID controller所規定的threshold時, RAID controller將會把超時的HDD判定為failed並且將他drop, 也許這個error correction可能是deep的情況. 關於LSI RAID controller所規定的threshold, LSI表示如下:
The time-out threshold is ten seconds.
前面講過, 當LSI RAID controller的polling timer達到300秒的時候, 便遍歷收集每顆硬碟的SMART資訊. 在TLER/ERC/CCTL部分, 如果取得的SCT ERC Timer偵測發現超過規定的threshold, 也就是10秒的情況下. LSI RAID controller便會將該超時的HDD給強制drop. 在這個案例下, SCT ERC Timer記載的value便會是0秒, 也就是unlimited. 如果帶有TLER/ERC/CCTL支持的HDD, 通常SCT ERC Timer設定會是在7 sec以下, 這時SCT ERC Timer<timeout threshold. 變不會將HDD給強制drop掉. 這將會提升對Storage System很大的穩定性.
LSI=> A drive will drop after 10 seconds
2011/02/04
>>Q: IMR模式下的LSISAS2008產品是Hardware RAID嗎???....
>>A: 根據我死纏爛打, LSI的回答: The 9240-series controller are software RAID. 不是Hardware RAID...
注意喔! 9240系列就是IMR模式, 意味著IMR模式的LSISAS2008產品都是software RAID....
2011/02/25
>>Q: DirectPDMapping作用是甚麼?..
>>A: DirectPdMapping is a flag which disables use of a backplane. It directly maps the drives instead of mapping the SAS expander.
DirectPdMapping exposes devices behind an expander to the OS. This does not disable the expander, but changes how it interacts with the controller and OS.
If you do not wish to expose the drives to the OS, this policy should not be enabled. The controller does indeed bypass the expander and move directly to directly PD mapping. The expander could be bad if it was enabled, but that would have nothing to do with it being enabled or disabled.