可使用以下过程确定是否需要为设备添加第一个读高速缓存设备。要确定是否需要多个设备,请参见何时添加多个读高速缓存设备 (CLI)。
hostname:analytics worksheets> select worksheet-000 hostname:analytics worksheet-000> dataset
hostname:analytics worksheet-000 dataset (uncommitted)> set name=arc.accesses[hit/miss] name = arc.accesses[hit/miss] hostname:analytics worksheet-000 dataset (uncommitted)> commit
hostname:analytics worksheet-000> dataset
按元数据命中和未命中细分的高速缓存 ARC 访问次数 ("arc.accesses[hit/miss=metadata hits][L2ARC eligibility]")
按数据命中和未命中细分的高速缓存 ARC 访问次数 ("arc.accesses[hit/miss=data hits][L2ARC eligibility]")
hostname:analytics worksheet-000 dataset (uncommitted)> set name="arc.accesses[hit/miss=metadata hits][L2ARC eligibility]" name = arc.accesses[hit/miss=metadata hits][L2ARC eligibility] hostname:analytics worksheet-000 dataset (uncommitted)> commit hostname:analytics worksheet-000> dataset hostname:analytics worksheet-000 dataset (uncommitted)> set name="arc.accesses[hit/miss=data hits][L2ARC eligibility]" name = arc.accesses[hit/miss=data hits][L2ARC eligibility] hostname:analytics worksheet-000 dataset (uncommitted)> commit
hostname:analytics worksheet-000> done hostname:analytics worksheets> done
hostname:> analytics datasets
hostname:analytics datasets> show Datasets: DATASET STATE INCORE ONDISK NAME dataset-000 active 1.27M 15.5M arc.accesses[hit/miss] dataset-001 active 517K 9.21M arc.accesses[hit/miss=metadata hits][L2ARC eligibility] ... hostname:analytics datasets>
在此示例中,数据集名称 arc.accesses[hit/miss=metadata hits][L2ARC eligibility] 对应于 dataset-001。
hostname:analytics datasets> select dataset-001
hostname:analytics dataset-001> read 86400 ... hostname:analytics dataset-001> done
当出现以下所有情况时,请考虑添加第一个读高速缓存设备:
每秒对元数据的适用于 L2ARC 的 ARC 访问至少有 1500 次未命中
设备中存在 ZFS 记录大小为 32k 或更小的活动文件系统或 LUN
hostname:analytics datasets> show Datasets: DATASET STATE INCORE ONDISK NAME dataset-000 active 1.27M 15.5M arc.accesses[hit/miss] dataset-001 active 517K 9.21M arc.accesses[hit/miss=metadata hits][L2ARC eligibility] dataset-002 active 780K 9.20M arc.accesses[hit/miss=data hits][L2ARC eligibility] ... hostname:analytics datasets>
在此示例中,数据集名称 arc.accesses[hit/miss=data hits][L2ARC eligibility] 对应于 dataset-002。
hostname:analytics datasets> select dataset-002
hostname:analytics dataset-002> read 86400 ... hostname:analytics dataset-002> done
当出现以下所有情况时,请考虑添加第一个读高速缓存设备:
每秒对数据的适用于 L2ARC 的 ARC 访问至少有 1500 次未命中
设备中存在 ZFS 记录大小为 32k 或更小的活动文件系统或 LUN