選擇儲存空間直接存取的磁碟機Choosing drives for Storage Spaces Direct

適用於:Windows Server 2016Applies To: Windows Server 2016

本主題指引您如何選擇儲存空間直接存取的磁碟機,以符合您的效能及容量需求。This topic provides guidance on how to choose drives for Storage Spaces Direct to meet your performance and capacity requirements.

磁碟機類型Drive types

儲存空間直接存取目前適用於三種類型的磁碟機:Storage Spaces Direct currently works with three types of drives:

NVMe (Non-Volatile Memory Express) 指的是直接位於 PCIe 匯流排的固態硬碟。 NVMe (Non-Volatile Memory Express) refers to solid-state drives that sit directly on the PCIe bus. 常見的板型規格為 2.5" U.2、PCIe Add-In-Card (AIC) 及 M.2。Common form factors are 2.5" U.2, PCIe Add-In-Card (AIC), and M.2. NVMe 提供更高的 IOPS 及 IO 輸送量且延遲更低,勝過現今所支援的任何其他磁碟機類型。NVMe offers higher IOPS and IO throughput with lower latency than any other type of drive we support today.
SSD 指的是透過傳統 SATA 或 SAS 進行連接的固態硬碟。 SSD refers to solid-state drives which connect via conventional SATA or SAS.
HDD 指的是提供大量儲存容量的旋轉磁性硬碟。 HDD refers to rotational, magnetic hard disk drives which offer vast storage capacity.

內建快取Built-in cache

儲存空間直接存取有內建的伺服器端快取。Storage Spaces Direct features a built-in server-side cache. 它是大型持久的即時讀寫快取。It is a large, persistent, real-time read and write cache. 在使用多種磁碟機類型的部署,它會自動設定為使用「最快速」類型的所有磁碟機。In deployments with multiple types of drives, it is configured automatically to use all drives of the "fastest" type. 其餘磁碟機則用於容量。The remaining drives are used for capacity.

如需詳細資訊,請查看了解儲存空間直接存取中的快取For more information, check out Understanding the cache in Storage Spaces Direct.

選項 1 – 使效能最大化Option 1 – Maximizing performance

若要在任何資料的隨機讀取與寫入間達成可預測且統一的子毫秒延遲,或達成極高 IOPS (我們已達到超過六百萬!) 或 IO 輸送量 (我們已達到超過每秒 1 Tb!),您應選擇「全快閃」。To achieve predictable and uniform sub-millisecond latency across random reads and writes to any data, or to achieve extremely high IOPS (we've done over six million!) or IO throughput (we've done over 1 Tb/s!), you should go "all-flash".

目前有三種方式可做到:There are currently three ways to do so:

All-Flash-Deployment-Possibilities

  1. 全 NVMe。All NVMe. 使用全 NVMe 可提供無與倫比的效能,包括最能夠預測的低延遲。Using all NVMe provides unmatched performance, including the most predictable low latency. 若您的磁碟機全為相同的模型,則沒有快取。If all your drives are the same model, there is no cache. 您也可混合較高耐力及較低耐力的 NVMe 模型,並將前者設定為替後者快取寫入 (需要設定)。You can also mix higher-endurance and lower-endurance NVMe models, and configure the former to cache writes for the latter (requires set-up).

  2. NVMe + SSD。NVMe + SSD. 搭配 SSD 使用 NVMe,NVMe 會自動快取 SSD 的寫入。Using NVMe together with SSDs, the NVMe will automatically cache writes to the SSDs. 這可讓寫入只在需要時於快取中進行聯合並取消暫存,以減少耗用 SSD。This allows writes to coalesce in cache and be de-staged only as needed, to reduce wear on the SSDs. 這可提供類似 NVMe 的特性,而讀取會直接由同樣快速的 SSD 提供。This provides NVMe-like write characteristics, while reads are served directly from the also-fast SSDs.

  3. 全 SSD。All SSD. 如同全 NVMe,若您的磁碟機全為相同的模型,則沒有快取。As with All-NVMe, there is no cache if all your drives are the same model. 若您混合較高耐力及較低耐力的模型,可將前者設定為替後者快取寫入 (需要設定)。If you mix higher-endurance and lower-endurance models, you can configure the former to cache writes for the latter (requires set-up).

    注意

    使用全 NVMe 或全 SSD 而不使用快取有一項好處,即您可從所有裝置取得可使用的儲存容量。An advantage to using all-NVMe or all-SSD with no cache is that you get usable storage capacity from every drive. 容量無須用於快取,對規模較小者頗具吸引力。There is no capacity "spent" on caching, which may be appealing at smaller scale.

選項 2 – 平衡效能及容量Option 2 – Balancing performance and capacity

若環境有多種應用程式及工作負載,其中幾項有嚴格的效能需求,而其中幾項需要大量的儲存容量,對於,您應選擇「混合式」,使用 NVMe 或 SSD 快取較大型的 HDD。For environments with a variety of applications and workloads, some with stringent performance requirements and others requiring considerable storage capacity, you should go "hybrid" with either NVMe or SSDs caching for larger HDDs.

混合部署可能性

  1. NVMe + HDDNVMe + HDD. NVMe 磁碟機會透過快取讀取與寫入來加快兩者的速度。The NVMe drives will accelerate reads and writes by caching both. 快取讀取可讓 HDD 聚焦於寫入。Caching reads allows the HDDs to focus on writes. 快取寫入會吸收高載,並允許寫入只在需要時以人工序列化的方式進行聯合並取消暫存,進而將 HDD IOPS 及 IO 輸送量最大化。Caching writes absorbs bursts and allows writes to coalesce and be de-staged only as needed, in an artificially serialized manner that maximizes HDD IOPS and IO throughput. 這會提供類似 NVMe 的寫入特性,而對於經常或最近讀取的資料也會提供類似 NVMe 的讀取特性。This provides NVMe-like write characteristics, and for frequently or recently read data, NVMe-like read characteristics too.

  2. SSD + HDDSSD + HDD. 如同上述項目,SSD 會透過快取讀取與寫入來加快兩者的速度。Similar to the above, the SSDs will accelerate reads and writes by caching both. 這會提供類似 SSD 的寫入特性,而對於經常或最近讀取的資料會提供類似 SSD 的讀取特性。This provides SSD-like write characteristics, and SSD-like read characteristics for frequently or recently read data.

    還有另外一項較奇特的選項:使用全部三種類型。There is one additional, rather exotic option: to use drives of all three types.

  3. NVMe + SSD + HDD。NVMe + SSD + HDD. 有了所有三種類型的磁碟機,NVMe 磁碟機會對 SSD 和 HDD 進行快取。With drives of all three types, the NVMe drives cache for both the SSDs and HDDs. 好處是您可在相同叢集中並排在 SSD 及 HDD 上建立磁碟區,全由 NVMe 進行加速。The appeal is that you can create volumes on the SSDs, and volumes on the HDDs, side-by-side in the same cluster, all accelerated by NVMe. 前者完全形同「全快閃」部署,而後者完全形同「混合式」部署,如上所述。The former are exactly as in an "all-flash" deployment, and the latter are exactly as in the "hybrid" deployments described above. 在概念上形同擁有兩個集區,且具備極度的獨立容量管理及錯誤及修復循環等。This is conceptually like having two pools, with largely independent capacity management, failure and repair cycles, and so on.

    重要

    我們建議使用 SSD 層,將最重視效能的工作負載放在全快閃裝置上。We recommend using the SSD tier to place your most performance-sensitive workloads on all-flash.

選項 3 – 將容量最大化Option 3 – Maximizing capacity

對於需要大容量、不常寫入的工作負載,例如封存、備份目標,資料倉儲或「冷」儲存空間,您應該結合幾個 SSD 用於快取與有很多較大型 HDD 用於容量。For workloads which require vast capacity and write infrequently, such as archival, backup targets, data warehouses or "cold" storage, you should combine a few SSDs for caching with many larger HDDs for capacity.

用於將容量最大化的部署選項

  1. SSD + HDDSSD + HDD. SSD 會快取讀取與寫入,以吸收高載並提供類似 SSD 的寫入效能,並於稍後對 HDD 進行最佳化的取消暫存。The SSDs will cache reads and writes, to absorb bursts and provide SSD-like write performance, with optimized de-staging later to the HDDs.

大小考量Sizing considerations

快取Cache

每個伺服器都必須具備至少兩個快取磁碟機 (備援所需的下限)。Every server must have at least two cache drives (the minimum required for redundancy). 建議您讓容量磁碟機數為快取磁碟機數的倍數。We recommend making the number of capacity drives a multiple of the number of cache drives. 例如,若有 4 部快取磁碟機,則 8 部容量磁碟機 (比例為 1:2) 展現的效能會比 7 或 9 部更一致。For example, if you have 4 cache drives, you will experience more consistent performance with 8 capacity drives (1:2 ratio) than with 7 or 9.

快取的大小應設為能容納您應用程式及工作負載的工作組,即其在任何時間點所有正在讀取及寫入的資料。The cache should be sized to accomodate the working set of your applications and workloads, i.e. all the data they are actively reading and writing at any given time. 此外即無其他快取大小需求。There is no cache size requirement beyond that. 若為一般部署,建議的起始量為容量的 10%。For typical deployments, a fair starting place is 10% of your capacity. 例如,若每個伺服器皆具 4 x 4 TB HDD = 16 TB 的容量,則每個伺服器 2 x 800 GB SSD = 1.6 TB 的快取便頗為合理。For example, if each server has 4 x 4 TB HDD = 16 TB of capacity, then 2 x 800 GB SSD = 1.6 TB of cache per server seems reasonable to us. 您稍後隨時都可新增或移除快取磁碟機進行調整。You can always add or remove cache drives later to adjust.

一般General

建議您將每個伺服器的儲存容量限為約莫 100 TB。We recommend limiting the total storage capacity per server to approximately 100 terabytes (TB). 每個伺服器的儲存容量愈多,停機或重新開機後 (如套用軟體更新) 重新同步資料所需花費的時間愈長。The more storage capacity per server, the longer the time required to resync data after downtime or rebooting, such when applying software updates.

每存放集區的大小上限目前為 1 PB 或 1,000 TB。The current maximum size per storage pool is 1 petabyte (PB), or 1,000 terabytes.

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