IBM TotalStorage DS6000 Series: Performance Monitoring and Tuning

12 IBM TotalStorage DS6000 Series: Performance Monitoring and Tuning

For most environments the DS6800 performs much better than an ESS. You might even

replace two ESS 800s with one DS6800. The sequential performance of the DS6800 is

excellent. However, when you plan to replace an ESS with a large cache (let’s say more than

16 GB) with a DS6800 (which comes with 4 GB cache) and you currently get the benefit of a

high cache hit rate, your cache hit rate on the DS6800 will drop down. This is because of the

smaller cache. z/OS benefits from large cache, so for transaction-oriented workloads with

high read cache hits, careful planning is required.

Figure 1-2 IBM TotalStorage DS6000 and ESS comparison

1.7.2 DS6000 series compared to DS8000

You can think of the DS6000 series as the small brother or sister of the DS8000 series. All

Copy Services (with the exception of z/OS Global Mirror) are available on both systems. You

can do Metro Mirror, Global Mirror, and Global Copy between the two series. The CLI

commands and the DS Storage Manager GUI look the same for both systems. DS6000 and

DS8000 now offer enterprise storage continuum solutions.

Obviously the DS8000 series can deliver a higher throughput and scales higher than the

DS6000 series, but not all customers need this high throughput and capacity. You can choose

the system that fits your needs since both systems support the same SAN infrastructure and

the same host systems.

It is very easy to have a mixed environment, with DS8000 series systems where you need

them and DS6000 series systems where you need a very cost efficient solution.

Logical partitioning with some DS8000 models is not available on the DS6000.

Figure 1-3 on page 13 presents in detail the comparison of both series.