SSD is gonna be the thing bumping the price there, depending on demand is whether you could get away with read intensive to drag costs down a bit on the Dell side…
What grade SSDs are they? What’s the warranty and performance?
You’re more likely to have RAID issues from my experience with Synology/QNAP type devices, especially if you did consider using the iSCSI route. Again the problem with iSCSI is you could compromise the Synology and remote wipe the LUN, then the immutability meant nothing. Direct Attached Storage is great in this regard.
If you absolutely need SSD, I hope you’re getting a 10Gbps or faster NIC in the Synology and the CPU/RAM to deliver the IO. I’m fully aware I sound like I’m just bashing Synology, and I don’t want to sound like that. They absolutely have a place in market but SSD high end performance isn’t their primary application in my experience. They typically use weak, low frequency & low core count processors. I take it you’re looking at an FS series Synology? Those seem best suited to the task out of the offerings. What disks? Something like the Samsung PM1643s?
Curve ball, you may find a vendor offering a warranty backed refurb of either current or -1 generation, those SSDs are normally far cheaper but much more durable. Then I’d ensure an extra disk’s parity to be safe.
If you go down the Synology route, I suggest giving yourself extra headroom for failure tolerance, completely isolating the device and seeing if it can be presented to a server via SAS/Thunderbolt for example, and using on a decent spec’d server. Then restrict all access and only allow outbound syslog or email for alert monitoring as an example.