存储空间直通的驱动对称注意事项Drive symmetry considerations for Storage Spaces Direct

适用于:Windows Server 2019、Windows Server 2016Applies to: Windows Server 2019, Windows Server 2016

如果每个服务器都具有完全相同的驱动器,则存储空间直通的效果最佳。Storage Spaces Direct works best when every server has exactly the same drives.

事实上,我们认识到这并不总是可行:存储空间直通设计为多年来运行,并随着组织需求的增长而扩展。In reality, we recognize this is not always practical: Storage Spaces Direct is designed to run for years and to scale as the needs of your organization grow. 现在,你可以购买 spacious 3 TB 硬盘驱动器;明年,找不到小型的。Today, you may buy spacious 3 TB hard drives; next year, it may become impossible to find ones that small. 因此,支持一定数量的混合和匹配。Therefore, some amount of mixing-and-matching is supported.

本主题介绍了约束,并提供了支持的和不支持的配置的示例。This topic explains the constraints and provides examples of supported and unsupported configurations.

约束Constraints

类型Type

所有服务器都应该有相同的驱动器类型All servers should have the same types of drives.

例如,如果一台服务器的驱动器类型为 NVMe,则所有服务器的驱动器类型都应该是 NVMe。For example, if one server has NVMe, they should all have NVMe.

NumberNumber

所有服务器的每种类型的驱动器的数量应当相同。All servers should have the same number of drives of each type.

例如,如果一台服务器有六个 SSD,则所有服务器都应当有六个 SSD。For example, if one server has six SSD, they should all have six SSD.

备注

在出现故障时或者在添加或删除驱动器时,驱动器数量可以暂时不同。It is okay for the number of drives to differ temporarily during failures or while adding or removing drives.

“模型”Model

建议尽可能使用相同型号和固件版本的驱动器。We recommend using drives of the same model and firmware version whenever possible. 如果无法做到这一点,请仔细选择尽可能相似的驱动器。If you can't, carefully select drives that are as similar as possible. 我们防止混合和匹配的驱动器具有急剧不同的性能或耐用特征 (,除非其中一个是缓存,另一个是容量) 因为存储空间直通会均匀地分配 IO,并且不会根据模型进行区分。We discourage mixing-and-matching drives of the same type with sharply different performance or endurance characteristics (unless one is cache and the other is capacity) because Storage Spaces Direct distributes IO evenly and doesn't discriminate based on model.

备注

可以混搭类似的 SATA 和 SAS 驱动器。It is okay to mix-and-match similar SATA and SAS drives.

大小Size

建议尽可能使用大小相同的驱动器。We recommend using drives of the same sizes whenever possible. 使用不同大小的容量驱动器可能会导致某些容量不可用,使用不同大小的缓存驱动器可能不会提高缓存性能。Using capacity drives of different sizes may result in some unusable capacity, and using cache drives of different sizes may not improve cache performance. 有关详细信息,请参阅下一节。See the next section for details.

警告

不同服务器上的容量驱动器大小不同可能会导致容量闲置。Differing capacity drives sizes across servers may result in stranded capacity.

了解:容量不平衡Understand: capacity imbalance

对于跨服务器和跨服务器的容量不平衡,存储空间直通是可靠的。Storage Spaces Direct is robust to capacity imbalance across drives and across servers. 即使不平衡情况很严重,所有功能仍将继续工作。Even if the imbalance is severe, everything will continue to work. 但是,如果不是每台服务器中都提供了某个容量,则该容量可能无法使用,这取决于多个因素。However, depending on several factors, capacity that isn't available in every server may not be usable.

若要查看发生此问题的原因,请考虑下面的简化图。To see why this happens, consider the simplified illustration below. 每个彩色框表示一个镜像数据副本。Each colored box represents one copy of mirrored data. 例如,标有 A、A' 和 A'' 的框是相同数据的三个副本。For example, the boxes marked A, A', and A'' are three copies of the same data. 为了实现服务器容错,这些副本必须存储在不同的服务器中。To honor server fault tolerance, these copies must be stored in different servers.

闲置容量Stranded capacity

如图所示,服务器 1 (10 TB) 和服务器 2 (10 TB) 已满。As drawn, Server 1 (10 TB) and Server 2 (10 TB) are full. 服务器 3 有更大的驱动器,因此它的总容量更大 (15 TB)。Server 3 has larger drives, therefore its total capacity is larger (15 TB). 但是,若要在服务器 3 上存储更多的三向镜像数据,则已满的服务器 1 和服务器 2 上也需要存在副本。However, to store more three-way mirror data on Server 3 would require copies on Server 1 and Server 2 too, which are already full. 服务器 3 上剩余的 5 TB 容量无法使用 – 它是“闲置”容量。The remaining 5 TB capacity on Server 3 can't be used – it's "stranded" capacity.

三向镜像,三台服务器,闲置容量

最佳放置Optimal placement

反过来,如果四台服务器的容量分别为 10 TB、10 TB、10 TB 和 15 TB 并且具有三向镜像复原能力,则可以有效地放置副本以使用所有可用容量,如图所示。Conversely, with four servers of 10 TB, 10 TB, 10 TB, and 15 TB capacity and three-way mirror resiliency, it is possible to validly place copies in a way that uses all available capacity, as drawn. 只要有此可能性,存储空间直通分配器就会查找并使用最佳放置,不会留下闲置容量。Whenever this is possible, the Storage Spaces Direct allocator will find and use the optimal placement, leaving no stranded capacity.

三向镜像,四台服务器,无闲置容量

服务器数量、复原能力、容量不平衡的严重程度以及其他因素会影响到容量是否会闲置。The number of servers, the resiliency, the severity of the capacity imbalance, and other factors affect whether there is stranded capacity. 为谨慎起见,通常会假设只有每台服务器中都提供的容量能保证可以使用。The most prudent general rule is to assume that only capacity available in every server is guaranteed to be usable.

了解:缓存不平衡Understand: cache imbalance

存储空间直通可以可靠地跨驱动器和跨服务器缓存不平衡。Storage Spaces Direct is robust to cache imbalance across drives and across servers. 即使不平衡情况很严重,所有功能仍将继续工作。Even if the imbalance is severe, everything will continue to work. 而且,存储空间直通始终使用所有可用缓存。Moreover, Storage Spaces Direct always uses all available cache to the fullest.

但是,使用不同大小的缓存驱动器可能不会一致地改善或如预期那样改善缓存性能:只有缓存驱动器较大的驱动器绑定的 IO 能够看到性能改进。However, using cache drives of different sizes may not improve cache performance uniformly or predictably: only IO to drive bindings with larger cache drives may see improved performance. 存储空间直通跨绑定平均分配 IO,并且不会根据缓存到容量的比率进行区分。Storage Spaces Direct distributes IO evenly across bindings and doesn't discriminate based on cache-to-capacity ratio.

缓存不平衡

提示

请参阅了解缓存,详细了解缓存绑定。See Understanding the cache to learn more about cache bindings.

示例配置Example configurations

下面是一些支持的和不支持的配置:Here are some supported and unsupported configurations:

支持:服务器之间的型号不同

前两台服务器使用 NVMe 型号“X”,但第三台服务器使用非常类似的 NVMe 型号“Z”。The first two servers use NVMe model "X" but the third server uses NVMe model "Z", which is very similar.

服务器 1Server 1 服务器 2Server 2 服务器 3Server 3
2 x NVMe 型号 X(缓存)2 x NVMe Model X (cache) 2 x NVMe 型号 X(缓存)2 x NVMe Model X (cache) 2 x NVMe 型号 Z(缓存)2 x NVMe Model Z (cache)
10 x SSD 型号 Y(容量)10 x SSD Model Y (capacity) 10 x SSD 型号 Y(容量)10 x SSD Model Y (capacity) 10 x SSD 型号 Y(容量)10 x SSD Model Y (capacity)

这是受支持的。This is supported.

支持:服务器内的型号不同

每台服务器混合使用一些不同但非常类似的 HDD 型号“Y”和“Z”。Every server uses some different mix of HDD models "Y" and "Z", which are very similar. 每台服务器总共有 10 个 HDD。Every server has 10 total HDD.

服务器 1Server 1 服务器 2Server 2 服务器 3Server 3
2 x SSD 型号 X(缓存)2 x SSD Model X (cache) 2 x SSD 型号 X(缓存)2 x SSD Model X (cache) 2 x SSD 型号 X(缓存)2 x SSD Model X (cache)
7 x HDD 型号 Y(容量)7 x HDD Model Y (capacity) 5 x HDD 型号 Y(容量)5 x HDD Model Y (capacity) 1 x HDD 型号 Y(容量)1 x HDD Model Y (capacity)
3 x HDD 型号 Z(容量)3 x HDD Model Z (capacity) 5 x HDD 型号 Z(容量)5 x HDD Model Z (capacity) 9 x HDD 型号 Z(容量)9 x HDD Model Z (capacity)

这是受支持的。This is supported.

支持:服务器之间的大小不同

前两台服务器使用 4 TB HDD,但第三台服务器使用非常相似的 6 TB HDD。The first two servers use 4 TB HDD but the third server uses very similar 6 TB HDD.

服务器 1Server 1 服务器 2Server 2 服务器 3Server 3
2 x 800 GB NVMe(缓存)2 x 800 GB NVMe (cache) 2 x 800 GB NVMe(缓存)2 x 800 GB NVMe (cache) 2 x 800 GB NVMe(缓存)2 x 800 GB NVMe (cache)
4 x 4 TB HDD(容量)4 x 4 TB HDD (capacity) 4 x 4 TB HDD(容量)4 x 4 TB HDD (capacity) 4 x 6 TB HDD(容量)4 x 6 TB HDD (capacity)

这是受支持的,但会导致容量闲置。This is supported, although it will result in stranded capacity.

支持:服务器内的大小不同

每台服务器混搭 1.2 TB SSD 和非常类似的 1.6 TB SSD。Every server uses some different mix of 1.2 TB and very similar 1.6 TB SSD. 每台服务器总共有 4 个 SSD。Every server has 4 total SSD.

服务器 1Server 1 服务器 2Server 2 服务器 3Server 3
3 x 1.2 TB SSD(缓存)3 x 1.2 TB SSD (cache) 2 x 1.2 TB SSD(缓存)2 x 1.2 TB SSD (cache) 4 x 1.2 TB SSD(缓存)4 x 1.2 TB SSD (cache)
1 x 1.6 TB SSD(缓存)1 x 1.6 TB SSD (cache) 2 x 1.6 TB SSD(缓存)2 x 1.6 TB SSD (cache) -
20 x 4 TB HDD(容量)20 x 4 TB HDD (capacity) 20 x 4 TB HDD(容量)20 x 4 TB HDD (capacity) 20 x 4 TB HDD(容量)20 x 4 TB HDD (capacity)

这是受支持的。This is supported.

不支持:服务器之间的驱动器类型不同

服务器 1 有 NVMe,但其他服务器没有。Server 1 has NVMe but the others don't.

服务器 1Server 1 服务器 2Server 2 服务器 3Server 3
6 x NVMe(缓存)6 x NVMe (cache) - -
- 6 x SSD(缓存)6 x SSD (cache) 6 x SSD(缓存)6 x SSD (cache)
18 x HDD(容量)18 x HDD (capacity) 18 x HDD(容量)18 x HDD (capacity) 18 x HDD(容量)18 x HDD (capacity)

不支持此操作。This isn't supported. 每台服务器中的驱动器类型应当相同。The types of drives should be the same in every server.

不支持:服务器之间每种类型的数量不同

服务器 3 有比其他服务器更多的驱动器。Server 3 has more drives than the others.

服务器 1Server 1 服务器 2Server 2 服务器 3Server 3
2 x NVMe(缓存)2 x NVMe (cache) 2 x NVMe(缓存)2 x NVMe (cache) 4 x NVMe(缓存)4 x NVMe (cache)
10 x HDD(容量)10 x HDD (capacity) 10 x HDD(容量)10 x HDD (capacity) 20 x HDD(容量)20 x HDD (capacity)

不支持此操作。This isn't supported. 每台服务器中每种类型的驱动器数目应相同。The number of drives of each type should be the same in every server.

不支持:仅使用 HDD 驱动器

所有服务器仅连接了 HDD 驱动器。All servers have only HDD drives connected.

服务器 1Server 1 服务器 2Server 2 服务器 3Server 3
18 x HDD(容量)18 x HDD (capacity) 18 x HDD(容量)18 x HDD (capacity) 18 x HDD(容量)18 x HDD (capacity)

不支持此操作。This isn't supported. 需要添加至少两个附加到每台服务器的缓存驱动器(NvME 或 SSD)。You need to add a minimum of two cache drives (NvME or SSD) attached to each of the servers.

摘要Summary

概括而言,群集中每个服务器的驱动器都应具有相同的类型,各类型驱动器的数量也应相同。To recap, every server in the cluster should have the same types of drives and the same number of each type. 支持根据需要混搭驱动器型号和驱动器大小,但需注意上述注意事项。It's supported to mix-and-match drive models and drive sizes as needed, with the considerations above.

约束Constraint 状态State
每台服务器中的驱动器类型相同Same types of drives in every server 必需Required
每台服务器中每种类型的数目相同Same number of each type in every server 必需Required
每台服务器中的驱动器型号相同Same drive models in every server 建议Recommended
每台服务器中的驱动器大小相同Same drive sizes in every server 建议Recommended

其他参考Additional References