The most noticeable operation in which WRITE SAME helps is with the creation of eagerzeroedthick virtual disks. Due to the fact that the zeroing process must be completed during the create operation, WRITE SAME has a dramatic impact on the duration of virtual disk creation and practically eliminates the added traffic that used to be caused by the traditional zeroing behavior.
The following chart shows the deployment time of four differently sized eagerzeroedthick virtual disks when WRITE SAME was enabled (in orange) and disabled (in blue). The enabling of WRITE SAME, on average, reduces the deployment time of these types of virtual disks to about 6x faster regardless of the size.
Figure 15. Eagerzerothick virtual disk deployment time difference (X-axis time in seconds)
WRITE SAME also works well in scale on the FlashArray. Below are the results of a test when four 100GB eagerzeroedthick virtual disks were deployed (with vmkfstools) simultaneously.
Figure 16. Total simultaneous deployment time for eagerzerothick virtual disks (Y-axis: time in seconds)
In comparison to the previous chart, where only one virtual disk was deployed at a time, the deployment duration of an eagerzeroedthick virtual disk without WRITE SAME increased almost linearly with the added number of virtual disks (taking 3.5x longer with 4x more disks). When WRITE SAME was enabled, the increase wasn’t even twofold (taking 1.6x times longer with 4x more disks). It can be concluded that the Everpure FlashArray can easily handle and scale with additional simultaneous WRITE SAME activities.