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By admin, May 15, 2013 7:29 pm

Saw this interesting post today, almost dated a year ago.

Q: Why does EqualLogic not support having active/active controllers?

A: This is a very good question. EqualLogic runs the active and passive controllers connected by a thick I/O pipe that effectively maintains the passive controller as a mirror of the active controller, this allows for near instantaneous failover in the event of a RAID controller failure – there is no need for the controller having to seize ownership of the failed controllers disks. This is supported by write cache mirroring and the write cache is cached to flash memory.

Note: The process of controller failover uses MAC spoofing and needs portfast and rapid spanning tree enabled on switches.

Q: Does EqualLogic support a Thin Provisioned LUN Space Reclaimer?

A: Not yet, this is in the pipeline.

Also came across this reply in Dell’s Forum.

Some terminology might be helpful here. Equallogic embeds their controller/filer/and disk shelves into one unit. The controllers are active/passive meaning only one controller is ever usable. The filer itself is tied directly to the disks. Other vendors handle this in different ways. Dell has chosen with the Equallogic system to do this.

Some vendors implement “raid” across the filers themselves (HP LeftHand’s network raid). Other vendors offer active/active controllers, or NetApp metrocluster functionality. Dell Equallogic does not.

We operate three Equallogic arrays in production use, and have never suffered a controller failure. When we preform firmware updates the unit reboots twice, taking it offline for 15 seconds. We do this during ‘quiet’ activity hours on our VMware, SQL Server, and Exchange clusters. They seem to handle the 15 second downtime without issue.

We have not seen the Active/Passive controller layout of the Dell Equallogic as a negative. The failure of an entire Equallogic filer (both controllers and both power supplies) is extremely extremely rare. There are no shared components between the controllers, they are functionally separate filers. The unit is right-sized for our organization and provides enterprise functionality at a fraction of the cost of a similar product that wold allow Active/Active enterprise level controllers, or Metrocluster functionality.

In summary:
> Dell Equallogic does not allow Active/Active Controllers, or full ‘raid’ between discrete units.
> Dell does not offer ‘Metrocluster’ or ‘Network Raid’ functionality like DRDB.
> Reboots of the entire SAN take 15 seconds (yes, really, as a customer, not Dell marketing) and do not cause any issue for us.

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By admin, May 14, 2013 12:00 pm

With the increasing popularity of my blog, I found more and more brutal force attack on WP admin login page. Today, I discovered a niche tool that actually does a bit of protection from this kind of automatic bot attack, of course, it won’t stop an experience hacker from trying.

IP                  Tried to log in as
78.154.105.23 admin (4 lockouts)
190.239.130.92 administrator (1 lockout)
180.190.221.208 admin (1 lockout)
194.27.149.159 administrator (1 lockout)
49.144.211.220 administrator (2 lockouts)
187.162.153.237 admin (1 lockout), administrator (2 lockouts), support (1 lockout)
1.171.228.91 admin (1 lockout), administrator (1 lockout), support (1 lockout)
186.101.201.68 admin (1 lockout)
126.68.40.134 admin (1 lockout)
189.224.56.236 administrator (1 lockout)
190.56.253.177 admin (1 lockout)
202.65.140.153 admin (1 lockout)
181.112.134.55 administrator (1 lockout)
79.101.247.52 administrator (1 lockout)
182.234.71.109 admin (1 lockout), administrator (1 lockout)

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By admin, May 13, 2013 11:07 am

Just received a message from my mum, one of my uncles passed away at age 78, I guess it’s becoming a norm for our age group to face this more and more.

So enjoy everyday and live our life!

Don’t Sweat the Small Stuff….and it’s actually all small stuff!

and last week I saw this on street, it did strike me again.

Matthew 6:34 – Bible
Therefore do not worry about tomorrow, for tomorrow will worry about itself. Each day has enough trouble of its own.

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By admin, May 10, 2013 4:17 pm

馬德里網球大師賽第二輪，世界一哥祖高域（Djokovic）碰到保加利亞小將迪米特羅夫（Dimitrov），二比三敗陣出局。

半夜在電視裏看直播，本來以為很快打完，結果一打三個多小時，打到香港天亮方休。比賽後段，全場為迪米特羅夫打氣，這個二十一歲的小將打到最後一分的時候，用手指在胸前劃了個十字，結果拿下了祖高域。

迪 米特羅夫冒起得很快，現在世界排名二十三，相信很快就可以躋身前十名。看他打球最有趣的地方，是他的動作活脫脫就是一個費達拿。無論正手反手，還是發球削 球，如果離遠了看，就是費天王現身，連發球前拍球起板的動作都一模一樣。除了步法還欠些火候，其他技術已非常成熟，所以看他打球，就像看見八、九年前的費 達拿。

很少有運動員打球姿勢和動作如此相似的，可見費達拿一定是迪米特羅夫的偶像，但模仿得這麼相似而有實效，猶如費達拿上身，真是世所罕見。費達拿是網球界不世之才，如今看來有接班人了，真令人高興。
希望這次他可以在馬德里的紅土場上跟費達拿相遇，然後看兩個出手一模一樣的人比賽，那就簡直是《西遊記》裏「真假猴王」的意境，一定刺激，一定好看。

李純恩

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By admin, May 10, 2013 9:39 am

In July 2010, Rackspace Hosting and NASA jointly launched a new open source cloud initiative known as OpenStack. The mission of the OpenStack project was to enable any organization to create and offer cloud computing services running on standard hardware. The community’s first official release, code-named Austin, was made available just four months later with plans to release regular updates of the software every few months. The early code comes from NASA’s Nebula platform as well as Rackspace’s Cloud Files platform. Early on in the history of the project, Ubuntu [9] Linux distribution decided to adopt OpenStack.

Just read about this new jargon, very interesting indeed as OpenStack was initiated by a leading web hosting company in US and there is an extremely self-conceited man in China who said that he will replace VMware with OpenStack within a year…Gosh!