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Storage Space lower performance than Mirrored RAID
Hi,
I've tested 2 SSD Samsung U.2 Gen4.0 on Windows 2019 Standard in the following congigurations:
1. Mirrored dynamic disks (RAID 1 in Computer management)
2. Storage Spaces - 2 way mirror, full spaces allocated
Theoretically, the Read and Write speed should be almost the same, but:
The first configuration (older technology: software RAID1) is 2 times faster on READ test with any kind of data blocks than Mirror Storage Space. This is strange, because Storage Space is relatively new and should have at least similar performance. Hope Microsoft will fix this situation with a patch.
2 Replies
I am confirming this strange behaviour also on Windows Server 2022. Storage Spaces ignores mirror and doing read only from one drive, while mirrored dynamic disk reads from 2 drives at once.
But dynamic disks doesnt support TRIM which leads into degraded write performance after some time.
I have noticed this as well. Instead of reading interleaving blocks from the two drives, it seems to try to read the same block from both at the same time, limiting the read speed to that of a single drive.
