分页： 1 / 1
冗余的SD卡配置
发表于 ： 2012年 7月 3日 16:50 星期二
由 MUDBOY
目前惠普的服务器上似乎没有这个冗余的配置。
但是DELL的机型上有类似的配置。
关于SD卡冗余是否必要，大家有什么建议么？
About the redundant SD card slots on HP's server, I know Dell has this sort of setup.
Has anyone got any ideas?
Re: 冗余的SD卡配置
发表于 ： 2012年 7月 3日 16:56 星期二
由 爱老虎油
Here is what one of the ISS Technology Specialists wrote last year about it。
Dell have been pointing out to customers that their Internal Dual SD Module (IDSDM) option for their servers is a key differentiator for customers running VMware ESXi, because it gives them RAID capabilities for SD cards.
Sounds great, but not really an enterprise customer solution, and here’s why:
1. The SD cards can only rebuild their “mirror” configuration during POST! So if a card fails, you can’t rebuild the mirror until the server reboots!
SD的重建只能在POST阶段完成，那就意味着，必须重启服务器。
2. It takes at least 3 minutes to rebuild a 1Gb SD card – so your server has to reboot and wait at least 3 minutes before it boots again to rebuild the mirror – longer if you have a bigger SD card!
重建1G的SD卡需要至少3分钟以上，如果容量更大，时间更长。
3. The SD cards run using AUX power, so you *cannot* remove an SD card while there is a power cable plugged into the server (even if the server is powered off) – if you do so, the mirror has to be rebuilt (that’s right, reboot the server and wait!).
SD卡的供电问题（AUX），决定了移除后（即使服务器power off下），mirror需要重建。
4. The SD card module has to have identical SD cards, or the secondary card has to have a higher capacity than the first card.
第二个SD卡的容量必须大于第一个SD卡。
5. The SD card module is a single controller based component with a standard USB 2.0 interface (takes over the onboard USB) – no dual channel or controller capability
SD卡冗余了，但是基于USB的SD控制器其实并没有冗余。
So, ultimately, if the customer requires high availability, this is not the solution – it is higher availability than a single SD card (gives you some extra time to plan an outage), but if the customer demands enterprise uptime, they should be going for
local mirrored RAID disks with online mirror, hot-swap, dual channel or Boot from SAN with dual paths/controllers/cache, etc.
Info available from Dell’s own whitepaper:
http://www.dell.com/downloads/global/pr ... per-en.pdf