The DS411slim can accommodate only 2.5-inch HDDs, so we installed Seagate ST9500325AS series disks into it. These Momentus 5400.6 series HDDs have a spindle speed of 5400 RPM, a capacity of 500 gigabytes, a cache buffer of 8 megabytes and SATA 3 Gbit/s interface. The rest of our testbed components were the same as in our earlier NAS tests. We enabled Jumbo Frames and created a disk volume with a shared folder and a user account with full access rights.
Synology has recently updated its firmware to version 1955. One of the important improvements is higher performance of ARM-based NASes. We want to check this out by benchmarking the DS411slim with the previous firmware (version 1922) first.
Notwithstanding its compact size, the DS411slim delivers high performance: an impressive 87 MB/s when reading from the striped array and almost 110 MB/s at writing. The processor turns out to be good enough for working fast with the fault-tolerant RAID5. Checksum calculations lower its performance by 5% at reading and 20% at writing, yet the speed remains high anyway. The performance hit is more serious with the RAID6: up to 10% at reading and 50% at writing. On the other hand, we guess that RAID6 is not a typical usage scenario for this NAS.
Let’s see if firmware 1955 is different.
The performance has indeed improved, especially at writing. The speed of reading is almost the same as before. Anyway, there is no reason not to update. Every publicly available firmware version is very stable and reliable.
You can increase your NAS capacity by connecting external disks. We checked out the speed of such devices using the same Seagate ST9500325AS disk connected via a USB 2.0 adapter or directly via a SATA-eSATA cable (we also used a power cable, of course).
The USB 2.0 interface limits the data-transfer speed. The maximum is 30-40 MB/s, which is much lower than with the internal disks. The eSATA interface is faster.
The ext4 file system makes no difference between the internal disk and the external eSATA one. So, the only problem is that the DS411slim has only one eSATA port.