2022/04/30

【數據中心設計】CDCP 學習筆記 - 數據中心 (Part 6-3) - Data Centre Design - Power Infrastructure

Grounding in the data centre 數據中心接地系統

主要作用:

  • Establish voltage reference
  • Clear electrical faults
  • Provide RF/ESD discharge path (SRG)
  • Carry lightning currents

接地阻值 < 1 Ohm,要求所有金屬物體都要接地,包括:機櫃,UPS,架高地板


Common Mode Noise (CMN) 

  • The voltage between neutral and ground
  • 要求:
    • Preference < 1 Volt
    • Acceptable up to 1% of line/phase to neutral voltage
    • The general recommendation by vendors < 3 Volt
  • 電纜越長,諧波越多,相位不平衡會增加CMN


Location of the isolation transformer? 隔離變壓器放哪裡?


  • Iso-Tx: delta-wye type 
  • Should be as close to the ICT equipment as possible
  • PDUs with built-in isolation transformer provides the best performance
  • Filtering of power disturbances
  • Reduction of Common Mode Noise (CMN)
  • K-13 type Tx is the most common type for data centres
  • In computer rooms with high harmonic content, one might want to consider upgrading the neutral to double size.


Forms of Distribution boards 配電櫃/箱的間隔

  • Form 1 - No separation
  • Form 2 - Separation of busbars from other functional units
  • Form 3 - Separation of busbars from all functional units and between all functional components but not their terminations
  • Form 4 - Separation of busbars from all functional units and between all functional components including their terminations

詳細分類可參考之前文章:【低壓制櫃設計】低壓制櫃的間隔和形式(Segregation & Form of LV Switchboard)


IP (Ingress Protection) grades 防塵防水等級

  • Most commonly found are IP20 / IP21 for UPS and other electrical systems in the data centre.
  • Selecting the digit 1 is sometimes useful as the UPS systems may be located in an area where overhead air conditioners are being applied. (一般情況UPS都為IP20)


Power quality: guidelines 電能質量要求

主要考慮參數:

  • Voltage: Nominal +/- 10% (EMSD要求voltage drop不可以超過 4%)
  • Frequency: Nominal +/- 10%
  • Common Mode Noise: < 1% of Phase to Neutral
  • Total Harmonics Distortion of Voltage (THDv): < 8% (non-linear load)
  • Total Harmonics Distortion of Current (THDi): < 12%


CBEMA / ITI(C) curves

  • CBEMA - Computer and Business Equipment Manufacturers Association
  • ITI(C) - Information Technology Industry Council
  • The CBEMA (ITI or ITIC) curve indicates what voltage levels are acceptable for ICT equipment. All manufacturers comply with the CBEMA curve.

  • 黃色高光區域:設備正常運行
  • 右上Prohibited Region:設備可能損壞
  • 右下No Damage Region:設備不會損壞,但亦不會運行


Label power versus actual power consumption(標籤上的功率 vs 實際使用功率)

  • Real power usage is typically 20-40% less than the label/plate power
  • based on the actual hardware configuration and other factors such as CPU load etc


Sizing power usage for the data centre (數據中心的電力需求估算)

Average Watt/Floor Area (sqm) - Power Density

  • Low-density data centre: 500 W/sqm
  • Medium-density data centre: 1,000-1,500 W/sqm
  • High-density data centre: 2,000-2,500 W/sqm
  • Extreme-density data centre: > 3,000 W/sqm

Rack Usage Power - Rack Power

  • Standard racks: 1-3 kW
  • Mixed racks: 5-8 kW
  • Blade servers: > 15 kW (as high as 28 kW per rack)
  • Add non-standard size equipment
    • Mainframes, storage, etc


  • UPS power: Add 35% to cater for a buffer.
  • Lighting power: can also refer to the Building Energy Code requirement to estimate
  • Cooling power: UPS power x 1.2 for refrigerant-based systems / UPS power x 1 for chilled water based cooling.
  • Safety factor: 20 ~ 25%


Sizing power usage for Generator-Set(後備發電機的電力需求估算)

主要考慮因素:

  • 實際後備負載需求:kVA/kW requirement of the installation attached
  • 設備啟動時的衝擊電流:Expected Inrush currents on the generator during operations
  • Harmonics returning from the connected installation


2022/04/25

【數據中心設計】CDCP 學習筆記 - 數據中心 (Part 6-2) - Data Centre Design - Power Infrastructure

Three-phase power cabling 三相電纜

對於香港的電力安裝工程,由 2009 年 7 月 1 日起,新固定電力裝置必須使用新顏色代碼電線。在舊的顏色代碼系統中,藍色和黑色分別代表相導體和中性導體。在新的顏色系統中,藍色和黑色分別代表中性導體和相導體(即採用相反的顏色代碼),故改用新顏色代碼可能會造成混淆。


現有的電力裝置內的舊顏色代碼電線並不需因此而更換,有關更改只適用於固定電力裝置,一般家居電氣產品並不會受到影響。為現有的固定電力裝置進行加裝、改裝及改善工程時,則需採用新顏色代碼電線。註冊電業承辦商及工程人員須依照本署制定的指引進行有關工程。


Conversion from three-phase to single-phase 三相線轉單相線


一般情況,配電箱Distribution Board (DB) 或配電盤Power Distribution Unit (PDU)實現三相到單相的轉換。大多數數據中心使用的UPS使用三相電,而ICT設備則較多使用單相電。設計和安裝三相電時,儘量讓三相Balance,建議imbalance不超過10%,最大也不能超過15%。


Proper power cable routing 合理安排電纜電線路徑

設計時,同一排的機櫃儘量安排不同相位的電線。如右側排布,每一排機櫃都有三相電線經過。
放大一排機櫃,每個機櫃如果是有Source A+Source B(即Dual Source)的話,那麼,一般的安排是每個機櫃的兩個source是同一個相位(假設相位一),但由不同的配電箱供電。左右兩邊的機櫃則由另外兩個相同的相位電供電(即相位二或相位三)


機櫃後備電源方案(一)—— Low availability

僅單一UPS提供後備電源。

中間任何一環故障都會當機(包括UPS, PDU, Power Supply Rail, Power Cable)


機櫃後備電源方案(二)—— Slightly better availability
仍為單一UPS提供後備電源,PDU提供兩條供電至機櫃內兩條Power Supply Rail,需要Dual Sources的設備可以接兩條Power Supply Rail進線。

中間可能故障的環節包括:UPS, PDU, Power Cable(單一source的設備)


機櫃後備電源方案(三)—— Improved availability
兩台不同迴路的UPS提供後備電源,供電至PDU後分別提供兩條供電至機櫃內兩條Power Supply Rail,需要Dual Sources的設備可以接兩條Power Supply Rail進線,仍有單一Power Supply Rail進線的設備可能出現single point failure。

中間可能故障的環節僅剩:Power Cable(單一source的設備)


機櫃後備電源方案(四 A)—— High-availability (example A)
兩台不同迴路的UPS提供後備電源,供電至PDU後分別提供兩條供電至機櫃內STS和機櫃內一條Power Supply Rail,STS之後提供一條Power Supply Rail,需要Dual Sources的設備可以接兩條Power Supply Rail進線,原本單一Power Supply Rail進線的設備增加了一條後備電源,穩定性提高。但如果STS或者Power Cable出現問題亦可能出現single point failure。

中間可能故障的環節僅剩:STS,Power Cable(單一source的設備)


機櫃後備電源方案(四 B)—— High-availability (example B)
方案四B機櫃內Power Supply Rail由兩條變為三條。仍有兩台不同迴路的UPS提供後備電源,供電至PDU後分別提供兩條供電至機櫃內STS和機櫃內兩條Power Supply Rail,STS之後提供一條Power Supply Rail,需要Dual Sources的設備可以接兩條Power Supply Rail進線,但進線可不與single source的設備共用,降低故障的概率,穩定性較方案四A高。但這種情況,仍然是如果STS或者Power Cable出現問題就可能出現single point failure。

因此,中間可能故障的環節為:STS,Power Cable(單一source的設備)


2022/04/24

【數據中心設計】CDCP 學習筆記 - 數據中心 (Part 6-1) - Data Centre Design - Power Infrastructure

Power supply quality 供電質量

近年來,通過硬件廠商和電力顧問的研究表明,數據中心的供電質量的好壞,可能導致各種問題,如設備故障、文件損壞、系統鎖死等。有時,用戶/客戶花費大量時間試圖診斷設備故障的原因,卻不知道原因可能往往出自供電的質量問題。另外,有些用戶認為UPS往往是萬能的,是可以解決所問題的,但是有些電力問題是可以通過其他地方進入系統的,比如接地線,防雷系統等等,導致系統出現故障。


Ever-increasing power requirements 不斷增長的電力需求

由於IT設備變得越來越耗電,導致許多數據中心超負荷運轉,因此數據中心的電力消耗大量增加。由於功耗增加,數據中心的熱負荷也在增加,導致供冷能力不足。

  • Projections of power consumption increase by approximately 2x every four years (電力需求每四年增加一倍)
  • Smaller packaging means more power density per sqm(更小的設備,意味著更高的power density)


From Power Plant to the IT Racks 從電廠到數據中心IT設備


The typical simple design of the power distribution system for the data centre(0)

最常見的供電邏輯就是變壓器的正常電網供電和後備發電機在自動轉換開關(ATS)之後將電力提供給UPS,UPS在最終供應給數據中心(當然,回路中每一級都有配電櫃/配電箱/保護開關等設備)


Automatic Transfer Switch(ATS)的作用

  • A device which selects power from one source or the alternate source
  • Break before making the principle
    • Required when having non-synchronised sources(轉換時間較長,前後電網不會自動同步)
  • Mechanical, therefore slow switching devices
    • Typically > 50 ms(會影響IT設備正常運作)


增強冗余能力方法(一)

    —— 2N Provision of UPS

The enhanced design of the power distribution system for the data centre(1)

N在設計中常常代表一套系統有N個設備,N+1則表示系統中另有1個後備設備,2N provision 則表示提供另一套冗余系統做後備。在(0)設計中,由於UPS為電子設備,有機會會發生故障,因此,在增強方案中提供了另一套UPS設備。這意味著兩套UPS設備同時運行,彼此分擔1/2負載,如果其中一個UPS因故障而進行維修或者定期維護,那麼另一個UPS將承擔所有負載。


增強冗余能力方法(二)

    —— 2N Provision of UPS + Normal + Essential(Generator)

The enhanced design of the power distribution system for the data centre(2-1)

The enhanced design of the power distribution system for the data centre(2-2)

香港的電力系統的穩定性十分之高(5個9,即99.999%),但也不能排除斷電的可能(變壓器及低壓配電櫃設備的定期維護(香港法例要求為至少5年一檢)),因此,從電網引入兩組進線(Dual Source)則會大大提高供電的穩定性。當一組進線維護時,負載可以暫時由其他變壓器給點,如果電網進線失電,另一組也可以臨時供電。由於提供兩組電源,對於有需要雙電源後輩的機櫃則需要配備Static Transfer Switch (STS)進行供電切換。

相比方案(2-1),方案(2-2)設置的好處是所有的設備都是在運行狀態,(2-1)中A/B的負載只使用了一邊的UPS負載,而(2-2)中所有設備都有負載。(2-2)雖然較為完美,但常常不是數據中心供電的首選方案,因為過多的冗余設備不僅增加了投資和建設成本,也增加了維護成本,機房的數量和面積也相應增加。


Static Transfer Switch(STS)的作用

  • A device which selects power from one source or the alternate source
  • Available in large units to switch at room level and smaller units to switch at the rack level
  • Break before making the principle
    • Required when having non-synchronised sources
  • - Electronic, therefore fast switching devices
    • < 20 ms(轉換時間比ATS更短,不會影響IT設備正常運作)


2022/04/19

【數據中心設計】CDCP 學習筆記 - 數據中心 (Part 5) - Data Centre Design - Light


數據中心對於照明的定義和計量單位

  • 對於照明光線要求的定義:
    • 工作區的照明:
      • 1)有助於有效地識別對象 
      • 2)有助於提高注意力和積極性 
      • 3)抵抗疲勞
      • 4)清晰地辨別危險情況
  • 光強度:Lumen 流明 
  • 特定區域的光強度:Lux 勒克斯
  • 例子:
    • 1000 Lumen 照攝於 1 sqm 內的是 1000 Lux
    • 1000 Lumen 照攝於 10 sqm 內的是 100 Lux
  • 數據中心最推薦測量位置,是在架空地板上方1m處測量(香港常用0.75m/0.8m作為工作平面測量)。


數據中心照度標準
  • EN 12464-1, light and lighting (工作場所的照明標準)
  • CIBSE Lighting Code(Chartered Institution of Building Services Engineers)
  • DIN-5035, Light and lighting
  • 大多數標準建議的平均照度:
    • 房間:500 Lux(一般),600 Lux(建議)
    • 走廊:200 Lux(一般),300 Lux(建議)
    • 服務區:150 Lux(一般),200 Lux(建議)
  • ANSI/TIA-942描述了以上三個級別的光線強度,取決於應用的位置和用途



數據中心燈具和排布
  • 有多種類型可供選擇(Preference is to use protected types,防撞型)
  • 應設置於:
    • At regular intervals 每隔固定的距離
    • In all aisles 在所有走道上
    • The back of the rack is typically more important than the front of the rack
    • 機架的背面通常比機架的正面更重要(機架背板常用於出線)
  • backup power supply from the standby generator set (發電機後備,消防燈具再另由後備獨立電池/集中電池組供電)
  • 熒光燈不應連接到為ICT設備供電的同一個UPS上(Fluorescent lights create a lot of electronic distortion)


數據中心應急燈具 
  • 應急燈具是在建築物停電時能使人員可以安全逃生。
  • BS 5588 / 5266, Emergency light standard(BS 5266是香港應急照明燈具最主要規例)
    • categories of emergency lighting systems 
    • their suitability for premises with different types of occupants
  • EN 50172 & EN 1838
    • Adequate artificial lighting should be provided in all common areas and escape routes and should be of a sufficient standard to enable persons to see to escape
    • Define lighting levels (1 Lux min, recommended 15 Lux)
  • 應急燈具的放置要符合當地的規例(香港最主要的既為FSD紅皮書,對於持牌場所即要求跟FSD circular letter,PPA104/104(A)(ENG/中文))
  • 其他要點注意:
    • 標準通常是以辦公室環境為假設,並不總是考慮到數據中心的應急燈具設置
    • 應急燈一般放置在天花板上,但當火災發生時,由於煙霧的影響,很難看到。
    • 一般要提供更多的應急燈具,為更加以確保數據中心的消防安全
    • 確保每個過道都有足夠的光線,至少在每個過道的末端,轉角位置都有應急燈具。
    • 在重要設備周圍應儘量提供更多的應急燈具
  • 手電筒燈
    • 使用適當的類型(質量、光強度)。
    • 確保定期檢查和更換電池
    • 熒光棒(Glow sticks)有時也是非常有用的(化學變化,短時間提供高光度)。



應急燈具及電池類型
  • 燈具類型
    • Incandescent
    • Fluorescent
    • LED (Light-Emitting Diode)
  • 電池類型
    • 獨立式 Standalone Type
      • Troublesome for maintenance on the light and battery
    • 集中式 Centralized Type
      • EPS (Emergency Power Supply)
      • EN 50171 (Central Power Supply Systems)
      • Easy centralized maintenance

2022/04/18

【數據中心設計】CDCP 學習筆記 - 數據中心 (Part 4-2) - Data Centre Design - Suspended Ceiling

假天花板/吊頂 Suspended ceiling

  • Standard: EN 13964, BS 476 part 21, 22, 23
    • Acoustic attenuation, fire resistance etc.
  • Suspended ceilings have many functions
    • Concealing of light fixtures, fire suppression piping, cabling, ducts etc.
    • Aesthetics
    • Used as a return duct for air conditioning
    • Reduction of volume in the room
  • Savings on fire suppression gas
    • Check local fire codes

安裝假天花/吊頂的最主要原因就是美觀。所有的电缆,管道被假天花隐藏起来,使房間看起來更整潔。在某些國家,假天花的安裝可以用来减少房内的空气計算量。通过这样做,可以降低灭火系统的气体需求量,因此,進一步可以节省成本。安裝假天花/吊頂的最主要原因就是可以作为热空气的回流通道。

    • The space between raised floor to suspended ceiling should be at least 2.60 metres (102", 8.5 ft) for racks 42 U
      • More height is required when using overhead pathways
        • At least 46 cm (18", 1.5 ft.) of clearance below water sprinkler heads and nozzles of gas-based fire suppression systems is required
          • Check cleanliness and cabling regularly


          高架地板的頂部到假天花板之間的高度需要至少2600mm
          假天花板內需保持幹凈和整潔,因為作為熱空氣的回流管道使用時,如果有大量的灰塵,會進入冷氣設備中。


          燃氣噴嘴和水噴淋頭的間隙很重要,以防止機架阻塞滅火系統。


          數據中心無假天花設計

          機房假天花的作用基本可以歸納為以下三點:
          1. 在采用機房專用空調的情況下,可利用假天花內空間作為機房專用冷氣系統的回風管。
          2. 假天花板上方便安裝各類照明燈具及嵌入式冷氣設備、各類送回風口、火災報警探頭和氣體滅火噴頭、各類溫濕度傳感器、攝像頭、探測器等機電末端產品。
          3. 假天花板遮蓋了天花內強、弱電各類金屬管、槽,消防報警和滅火系統各類管線,管道式新風機及通風系統各類管道及其保溫層,弱化了假天花內各專業管線、閥門、通風管道等協調的裝修要求,美化了環境,提高了機房的整體效果。
          傳統的數據中心方案設計,大部分以上客戶只要經費足夠,都喜歡做假天花,讓機房里天花平面垂直。但是呢,實際使用起來效果真的好嗎?(現實世界的數據中心一定不會像最上面張圖一樣整齊)

          其實,假天花做完後給後期維護工作帶來諸多麻煩,而且假天花的安裝工藝看似簡單,但是裝得平平整整也不易,基本上後期都會被維護的拆來拆去,變得不平整,歪歪斜斜。而且,如果利用假天花美的空間作為回風天花,清潔起來也會異常麻煩(雖然可能成年都不會清潔一次)。



          所以,美觀好看雖然是主要原因,但並不是核心訴求,機房本來就是工業化的場所,沒必要裝飾得很好看。上面張機房圖,難看嗎?並不,反而很整潔。另一方面,從後期維護成本和工作量來看,保溫管哪里漏水直接看到,燈具壞掉可以直接維修,電纜電線可以方便進出和走線。因此,無假天花的設計有助於長期運維及監控。

          【數據中心設計】CDCP 學習筆記 - 數據中心 (Part 4-1) - Data Centre Design - Raised Access Flooring



          架空地板的主要種類 Raised Access Floor Types 

          Die-formed welded steel construction

          • 內部是空心的
          • "穿孔地板"
          • 冷氣可以從地板下穿透至地板之上

          Die-formed welded steel shell with a cement-filled core

          • 內部有水泥或混凝土結構或填充物
          • 增加地板硬度,承受更多的重量
          • 更重,可以降低地震影響

          其他仍在使用的種類:

          • Galvanized floors (be aware of zinc whiskers)(鍍鋅的,有害,被鋅污染。極細的鋅金屬,可能會進入數據中心系統的電路中,影響系統。)
          • Wood filled floors(木材填充,市場上幾乎已經沒有這種地板了)
          • Carbon fibre floors(碳纖維地板)

          The top finish is normally HPL - High-Pressure Laminate(傳統架空地板上覆蓋有乙烯基飾面,這是一種塑料飾面。這通常被稱為HPL)

          Various grades are available depending on application(不同的等級有不同的應用)


          載荷相關考慮因素 Loading factors

          Uniformly Distributed Load (UDL)(均勻分布載荷)

          • Applied over the entire area of the panel/tile(負載均勻地分布在整個地板的表面區域)
          • Typically imposed by stationary furniture and equipment without legs
          • Rating specified in kilo Newton's per square metre (kN/m2 ) or Lbs/ft2

          但是,這種負載的分佈方式在數據中心幾乎不適用,因為大多數設備都是站在腳輪(滾動輪)或腳上的。大部分的機架一般是一個框架,而不是一個完整的平面底座。

          Concentrated Load/Point Load (CL/PL)(集中載荷/點載荷)

          • Applied on a small area(壓力集中於某一區域)
            • In most standards, a point is defined as 25 mm2 / 0.0387 inch2(在大多數標準中,一個集中的點被定義為25sqmm)
          • Typically imposed by stationary furniture and equipment with legs/casters
          • Concentrated point load is applied to the surface of the panel resulting in panel deflection and possible permanent set

          地板最薄弱的地方一般是在地板的對角線中心,地板的側面由於靠在弦桿和基座上而得到加強,有額外的支持,因此這一部分有更大的強度。


          Rolling (RL)(滾動載荷)

          • Typically imposed by equipment on wheels moving across the raised access floor surface
          • Defined by the number of passes, size and hardness of the wheel and the combined weight of the wheeled device and its contents on each wheel
          • Rolling loads are more damaging on the raised floor panel than any other type of load

          滾動載荷比其他類型的載荷對高架地板的損害更大。因為滾動可能導致劃痕,而且還極大地拉伸了地板。當滾輪在凸起的地板上滾動時,會產生波浪效應,更加對地板產生負面影響。為了保護地板,可以通過覆蓋地板來提供保護。可以使用鋁等金屬板,由於堅固和良好的延展性,而且也方便後期維護。


          載荷相關標準 Standards

          European Norm EN 12825

          • The raised floor must be capable of withstanding a uniform load of 1,220 kg/m2 or a load of 454 kg on any 6.5 cm2, with a maximum deflection of 2.5 mm

          UK-PSA MOB PF2 standard (Property Services Agency)

          • Light: 1.5 kN over 25 mm2 (PL), not more than 6.7 kN/m2 (UDL)
          • Medium: 3.0 kN over 25 mm2 (PL), not more than 8.0 kN/m2 (UDL)
          • Heavy: 4.5 kN over 25 mm2 (PL), not more than 12 kN/m2 (UDL)
          • Extra Heavy: 4.5 kN over 25 mm2 (PL), not more than 12 kN/m2 (UDL)
            • Also sustain a total load of 11 kN applied equally on four points, each point 25 mm2 on a 200 x 200 mm square area

          HeavyExtra Heavy對於所描述的兩種載荷看起來是一樣的,但Extra Heavy還必須能夠在四個點上承受11kN的載荷,而且每個點都是25sqmm,且四個點的總面積不超過200×200mm。

          US-CISCA (Ceiling and Interior Systems Constructors Association)

          NFPA 251, fire-resistant for at least 1 hour

          IEC-61000-4-2, anti-static properties


          一般指引 General guidelines

          • Raised floor height to be at least:
            • 400 mm
            • preferably 600 mm
          • When pathways are used under the floor these should be kept low and if possible ventilated。
          • All openings must have plastic edging
          • All openings must be properly sealed
            • Air leakage prevention
          • Air-conditioning frame to raised floor clearance
          • Don't make it a storeroom or garbage bin
          • Keep it clean, some fires start under the floor

          40厘米的地板高度,可以作為冷氣的供風空間,以冷卻3-4kW的機架。如以地板作為供風通道,須用塑料或橡膠封邊密封地板上的開口,以防止泄漏。

          確保冷氣設備直接架設在架空地板上,冷氣設備要另設結構支架做支撐並與地板結構保持距離。這樣可以確保冷氣設備的振動不會影響到地板上的設備。

          保持架空地板的乾淨和整潔,且無在地板之下儲藏物品。


          架空地板的接地 Grounding of raised floor

          The raised floor needs to be connected to the ground wire

          Signal Reference Grid (SRG)

          • Provide an equipotential plane for the equipment contained within computer/server rooms
          • Provides a low-impedance path for high-frequency noise currents to dissipate before they cause the breakdown of equipment
          • All racks must be individually bonded to the SRG(確保所有rack都要連接到SRG!)
            • Serial bonding is not allowed
          • Ideally created via braided copper wire or flat copper strip connected to every other pedestal or surrounding frame (IEEE-1100)(減少skin effect)
          • Acceptable via grounded raised floor frames
            • Hanging bolted frame must be free of corrosion


          在地板上開洞 Cutting holes in a raised floor tile

          • Using the correct practice for cutouts in a raised floor tile will ensure the integrity of the tile
          • Draw a cross on the tile as indicated below
          • When making a cut-out you should never touch a line and more importantly, never touch two lines and obviously avoid the corners


          坡道 Ramps

          • Ramps are used for access to the raised floor
          • General guideline: 1 to 12 ratio
            • 400 mm (16", 1.3 ft), raisedfloor,
              • => 4.8 metres (190", 15 ft) length of ramp
            • 600 mm (24", 2 ft) raised floor,
              • => 7.2 metres (285", 24 ft) length ramp
          • Width approx. 2 metres (78", 6.5 ft)(基本上大於1.8m寬度已經滿足大部分設備的運輸要求)
          • Landing platforms should be the same in square dimensions(為了安全起見,強烈建議設置扶手。)
          • Most building codes dictate the use of handrails for safety
          • Other considerations -
            • Local rules such as Disability Acts have often an impact on the design of the ramps, runways, door sizes etc.
            • Some guidelines, but not limited to
              • Wheelchair routes shall have a width of at least 1 metre / 3 ft.
              • Where turning points are expected 1.5 metre / 5 ft. is required
              • Handrails need to be of a special design
            • Refer to local guidelines and regulations



          2022/04/10

          【數據中心設計】CDCP 學習筆記 - 數據中心 (Part 3-2) - Data Centre Design - Locations, Building and Construction

          數據中心及其配套設施 The Data Centre and supporting facilities


          保管區 Holding area

          保管區是接收設備的區域。可以是建築物的裝卸區。但必須有足夠的空間來處理設備。

          不要在數據中心本身拆開包裝,因為會散布包裝上的灰塵。也不要把箱子放在計算機房里。安排適當的垃圾處理設施。這個區域需要安保措施,以管理重要的資產。

          如果適用的話,可以在保管區配備保安或者安排CCTV。

          Purpose

          • Aimed at providing an area where goods can be received, unpacked, physically inspected, and prepared for movement into the staging area

          Requirements

          • Easy access for external supply (i.e. loading bay and route to staging area)(連接至卸貨區)
          • Spacious
          • Proper garbage disposal(IT設備一般包裝材料較多)
          • Secure


          集散區 Staging area

          一旦完成設備的開箱工作,就可以將其轉移到集散區。這個區域應該與保管區分開。

          為了防止對現有設備潛在的幹擾,開箱的新設備最好連接到一個單獨的PDU,該PDU連接到一個單獨的UPS系統。

          Purpose

          • Provides an area where equipment can be acclimated, inspected, configured (H/W & S/W) and safely tested to ensure deployment readiness(共測試獨立的硬件和軟件)

          Requirements

          • Separate and secure space
          • Separate network if possible / needed
          • Separate PDU (Power Distribution Unit)
          • Environmentally controlled and monitored
          • Fire protection and other safety measures


          電腦房 / 伺服器房 Computer / Server room

          機房應具有較低的電磁場水平,電磁場水平較高會導致設備信號中斷。不要在計算機房內放置變壓器、UPS系統、裝有通風裝置的電池系統。

          Purpose

          • Provides a safe production environment where equipment can be expected to run on a 24x7 basis with minimal risk of interruption

          Requirements

          • Separate and highly secure space
          • Protection and control of power quality
          • Environmentally controlled and monitored
          • Low EMF (Electro Magnetic Field) radiation levels
          • Fire protection and other safety measures

          媒體儲存區 Media storage area

          媒體存儲區是存儲母帶和文件以及備份磁帶、CD/DVD的地方。這個房間應該使用理想的溫度和濕度設置對媒體進行環境控制。理想情況下,媒體存儲區最好在單獨另一個完全不同的建築物內或在不同的樓層。

          Purpose
          • Provides a safe, secure and conditioned environment where media (documentation, magnetic tapes, CD-ROMs etc.) can be stored in a controlled manner
          Requirements
          • Separate and secure space
          • Environmental controlled and monitored(magnetic 材質不易抗低溫和高濕度環境)
          • Fire protection and other safety measures
            • Preferably highly sensitive smoke detection systems
            • Shelter/Bunker(有較高防火等級)


          不間斷電源房 UPS room

          UPS系統應該儘量設置在一個單獨的房間里。因為,UPS系統的電磁波會影響IT系統。

          如果不得不在伺服器房安裝UPS系統,盡量在UPS和ICT設備之間至少預留有2-3個Rack空間。

          UPS機房內的冷氣和防火設備是極為重要的。

          Purpose
          • Provides a safe, secure and conditioned environment where power protection and conditioning systems can operate on a 24x7 basis
          Requirements
          • Separate and secure space
          • Environmental controlled and monitored
          • Fire protection and other safety measures
          Note: in some cases, a small rating UPS could be located within the computer room(大型數據中心UPS房常常與server room分開,有利於UPS房設備,例如電池,的後期維護)


          電池房 Battery room

          電池室最好設置為一個獨立的房間,盡管大部分數據中心的UPS系統和電池在同一個房間。

          Purpose
          • Provides a safe, secure and conditioned environment where batteries can be stored
          Requirements
          • Separate and secure space
            • Ideally separated from UPS room
          • Environmental controlled and monitored(電池房溫度不能過高,過高會影響電池壽命)
          • Fire protection and other safety measures
          • Vented; if needed/required

          傳統的鉛酸蓄電在充電時,H2SO4卻不斷地生成,會產生的氣體是氧氣和氫體。氫氣具有高度爆炸性,如果發生火花,可能會出現爆炸。因此,良好的通風至關重要。

          不過隨著科技的進步,現在使用的鉛酸蓄電池,當充電後期時只是正極析氧而負極不產生氫氣,同時產生的氧氣通過多孔膜,電池內部上層空間等位置到達負極,氧化海綿狀的鉛,這樣生成水,可以減少維護或免維護。現在使用的鉛酸蓄電池已實現了免維護密封式結構,這是鉛酸蓄電池在原理和工藝技術上最大的改進。

          另外,由於鋰電池的成本越來越低,由於空間相比鉛酸電池小,而且又較鉛酸電池環保,因此,越來越多的ups已經採用鋰電池。


          維護走道 Service corridor

          如果沒有維護走道,為了維修AC等設備,維護人員需要進入數據中心機房,而理想的情況是盡量減少進入數據中心機房。維護走道的設置如下圖,在空間有限的情況下,添加維護走廊增加了很多成本。

          Purpose
          • Provides a secure area where supporting facilities can be serviced and monitored on a 24x7 basis without disturbing the computer room(利於設備後期維護,不用走入server room)
          Requirements
          • Separate and secure space
          • Environmental controlled and monitored
          • Fire protection and other safety measures
          AC equipment w/o service corridor

          AC equipment c/w service corridor


          後備發電機房 Standby generator set room/area

          發電機燃油箱的大小和儲存需要根據當地的規定來確定。在不同的地區,油箱的放置位置有不同的規定和限制。

          Purpose
          • Provides a safe and secure area where the standby generator set can be located to allow for safe operation with minimal disturbance
          Requirements
          • Separate and secure area
          • Fire protection and other safety measures
          • Fuel tanks could be located underground or above ground
            • Regulations apply and need to be reviewed before making a decision on which type to use(留意香港油缸房要符合FSD 2022年3月生效的新例)

          進線室 Meet-Me / Entrance room

          這個房間是網絡運營商或其他外部數據和電信線路進入大樓的地方,與大樓的交接點,也可以成為進線轉接室。一般在首層或地下室。需要留意提供電磁屏蔽設施,也應該儘量遠離高壓電纜的進線路徑。(有時會叫Cable Lead-in Room或者Cable Transfer Room)

          Purpose
          • Provides a safe production environment where the carrier handover point equipment can be expected to run on a 24x7 basis with minimal risk of interruption
          • Note: sometimes located within the computer room
          Requirements
          • Separate and secure space
          • Protection and control of power quality
          • Environmental controlled and monitored
          • Fire protection and other safety measures


          安保室 Security room

          Purpose
          • Provides a secure area where security functions can be undertaken on a 24x7 basis
          Requirements
          • Separate and secure space
          • Protection and control of power quality(UPS backup)
          • Fire protection and other safety measures


          網絡運營控制室 NOC (Network Operations Control)

          Purpose
          • Provides a secure area where the ICT infrastructure and supporting facilities can be monitored and controlled on a 24x7 basis
          • Note: sometimes combined with the security room
          Requirements
          • Separate and secure space
          • Protection and control of power quality
          • Environmental controlled and monitored
          • Fire protection and other safety measures

          2022/04/09

          【數據中心設計】CDCP 學習筆記 - 數據中心 (Part 3-1) - Data Centre Design - Locations, Building and Construction

          數據中心選擇合適的地點不僅需要考慮到新數據中心的技術要求,而且還涉及到從商業角度的許多方面。然而,現實中,業主所做出的選擇,往往更看重地址的商業和營銷方面。因此,這可能會導致地點選擇上對於技術評估方面的規定和要求過多。

          位於香港新界西貢區將軍澳的高端數據中心MEGA Plus


          Site selection criteria

          • Site selection is difficult

          • - Technical requirements evaluation(技術方面考量)
          • - Decision making process/business evaluation(商業方面考量)

          • Technical evaluation

          • - Often done by engineers
          • - Want the best to meet design criteria

          • Business evaluation

          • - Done by senior management
          • - Return On Investment (ROI) / cost
          • - Prestige
          • - Location

          • Proper planning, analysis and studies must be performed to avoid impact after the data centre construction on:

          • - High-availability
          • - Reliability
          • - Manageability
          • - Scalability
          • - Cost of operations
          • - Non-compliance to standards

          • Select sites that cater for current needs and future (planned) growth and business requirements(時刻考慮將來的需要)


          Location evaluation

          • Potential natural hazards

          • - Lightning, flooding, typhoons
          • - Forest fires
          • - Seismic activity (earthquake)

          • Potential man-made hazards

          • - Flight path(不要建在離機場跑道較近的地方)
          • - Tunnels, lakes(不要建在隧道上方,水域附近的地方)
          • - Train station/airport (Train station的震動關係)
          • - RF towers(Electromagnetic signal interference)
          • - Power distribution network(Electromagnetic fields)
          • - Industrial pollution(air contamination)

          • Proximity evaluation to emergency services / first responders

          • - Fire, police, medical facilities(不要太接近這些設施)

          • Proximity to the neighbourhood (urban/industrial)(不要太接近居民區:backup generator的噪音;不要太接近工業區:空氣污染)

          • Proximity to public transport and public roads(交通儘量便利)

          • Proximity to 'high risk' targets(避免靠近以下地點)

          • - Embassies
          • - Government buildings
          • - Power stations
          • - Radio/TV stations

          • Convenience should not overrule security!


          Building evaluation

          • Building evaluations;

          • - Rent / Buy / Build
          • - History of the building and/or area (是否以前有過flood, fire etc.)
          • - Building codes(加改建有無要求)
          • - Level/floor within the building(儘量不要在首層Ground Floor和頂層Top Floor)
          • - Space required for each functional area incl. potential expansion(server room space? UPS room space?)
          • - Security
          • - Glass windows/panels(儘量不要用玻璃幕牆,不如混凝土牆堅固)
          • - Floor loading(IT設備越來越重, loading requirement)
          • - Slab to slab height(有無條件加raised floor,天花是否夠headroom走線)
          • - Power capabilities(Redundancy and capacity)
          • - Network capabilities(Redundancy and diversity)(Diversity更重要,儘量選擇多於一家網絡設備供應商)
          • - External supply capabilities(Re-fueling of standby generator tanks / Delivery of heavy/big equipment and route to the data centre)(設備運輸問題, loading for delivery route)

          • Budget to build / budget to run(技術始終要受到預算的限制)


          香港的數據中心

          在香港,設置數據中心的選址途徑有多種,包括:

          • 改裝現有工業大廈
          • 在政府售賣的未發展之土地上設置
          • 在公開市場購買或租用土地/樓面空間

          有關香港數據中心選址的詳細介紹可參考:Link


          改裝現有工業大廈

          本港許多現有的工業大廈,樓底高、樓面負荷量大和樓層間隔具彈性,可改裝成為數據中心。視乎所需空間,數據中心可佔用部分或全幢工業大廈。

          在香港,大型數據中心多匯聚於荃灣、葵涌、沙田、觀塘、九龍灣、新蒲崗、柴灣及將軍澳等地區。

          工業大廈位處地段的土地契約上包含土地使用及其他方面的限制。位於「工業」、「商業」或「其他指定用途」註明「商貿」地帶的工廈業主可申請將合資格工業大廈的一部分改為數據中心用途,並免繳豁免書費用。興趣在工業大廈設置數據中心的人士應查閱地契是否已准許作數據中心用途。若否,業主可申請修訂土地契約或臨時豁免書。