Home > Workload Solutions > SQL Server > Guides > Reference Architecture Guide—Ready Solutions for Microsoft SQL: Design for Dell EMC XtremIO > XtremIO X2 inline data reduction
The XtremIO X2 all-flash array’s wide range of features includes inline data reduction. Data reduction services work by first deduplicating data: If two blocks are the same, deduplication uses metadata to track the duplicate block. Metadata is maintained in memory for fast access, and only unique blocks are written to storage, thus saving space on the flash drives.
After deduplication, the XtremIO X2 array compresses data, reducing the amount of array space that is used by unique blocks of data. The compression space savings means that data blocks are stored in the most efficient manner. The value of inline data reduction is the resulting ability to consolidate more databases to the XtremIO X2 array. As part of our tests, we captured inline data reduction savings for SQL Server on RHEL. Table 10 shows the storage configuration and inline data reduction savings for SQL Server.
Table 10. XtremIO X2 configuration and data reduction ratios
Data volume |
Volume size (GB) |
Host-accessible size (GB) |
Unique physical space (GB) |
Data reduction ratio |
RHEL DATA1 |
900 |
529.42 |
152.24 |
3.48 to 1 |
RHEL DATA2 |
900 |
505.18 |
141.66 |
3.57 to 1 |
Totals |
1800 |
1034.6 |
239.9 |
3.52 to 1 |
We provisioned two 900 GB data LUNs for each database. Of the 900 GB of LUN space, the database used 529.42 GB on DATA1 and 505.18 GB on DATA2. In Table 10, Host-accessible size represents the space that is used without any data reduction. If DBAs were to query the amount of space used, the database would report a total of 1034.6 GB. The storage array’s data reduction technology is transparent to all applications, meaning that it presents no complexity or special requirements. However, it also means that DBAs should work with the XtremIO X2 administrator to gain an understanding of the data reduction savings.
As shown in Table 10, the actual space that is used on the XtremIO X2 array is 152.24 GB for DATA1 and 141.66 GB for DATA2. The benefit of data reduction is expressed in a ratio. For example, 529.42 divided by 152.24 is a 3.48 to 1 space savings on the DATA1 LUN. On the DATA2 LUN, the data reduction savings were similar at 3.57 to 1. Data reduction ratios are useful, but perhaps a more powerful way to express the data savings is to compare the host-accessible size to the actual space used—unique physical space. The host-accessible size was 1034.6 GB and the actual space used was 239.9 GB, a total space savings of 794.7 GB. Expressed as a percentage, the space savings achieved is 71.5 percent, which is substantial for SQL Server databases.