Down the Rabbit Hole

So, starting out to look into the options for photo management, I find that some users of Lightroom have their storage located on a Synology NAS, but use an iSCSI connection. I was not familiar with iSCSI, though many (many) years ago, used SCSI devices. The iSCSI connection appears easy enough to create on the Synology. But also find that the Mac does not come with a native iSCSI initiator to connect to the iSCSI target you create on the Synology.

A thread on the MacRumor discussion boards reads: 

"SCSI is a virtual SCSI channel over TCP/IP network. You may call it niche, since it's mostly used in large scale network storage system, and seldom used by home / small office users, but it's not some legacy technology.
An iSCSI target (or the "network hard-drive" if you prefer) is not necessary to be a "SCSI" device -- the iSCSI is merely a pure-virtual software level, so that the initiator host (the Computer) can tell the target (the hard-drive) where to fetch data. The storage device will translate SCSI command to HFS/EXT-3/EXT-4 file system access command, so that it may access the real physical storage. You can imagine it like an virtual hard-drive .ISO image file used by VMWare or Parallel. For example, a medium level NAS from QNAP or Synology may use 4 SATA3 hard-drives, configure to RAID 5, format main partition to EXT-4, create a virtual logic partition that takes 20% of total usable spaces, and assign it as iSCSI target. 
When you mount an iSCSI target on to your Mac OS X desktop, it's different from an SMB/AFP shared volume. An iSCSI target operates just like an ordinary USB or 1394 external disk: you can format the volume with Disk Utility, paste icons, create directory, copy files, delete files, and grab deleted files back from the system trash can."

There are solutions for Mac, the principal one seeming to be GlobalSAN, which isn't free. I have a Windows7 VM running (under Parallels) on my Mac, and Windows is supposed to have native iSCSI capability, but I'd really prefer to have any such connection running under my host OS, rather than a VM. There is another free solution from Kernsafe for the Mac. So, maybe iSCSI, could be a solution I sought for how to interface the image editor/browser with the storage solution I use.  Lightroom is still something I need to evaluate.

There's a thread on the Adobe forums about the topic of keeping the primary library on a NAS. Though there's no clear answer, some people seem to have no problem, others are wary. No one mentioned using iSCSI, which would address the speed concerns that some did raise.

Picasa Starter is for Windows, darn it. I have a Windows laptop, but this isn't really the optimal solution, since I'm mostly Mac in my workflow. Though it appears that Picasa Starter hasn't been updated since April 2012, it does mention its compatibility with the current version of Picasa (3.9), so although the lack of continued development is a concern, it might work in the short term if I decided to use my Windows laptop; it is possible to locate the Picasa database on a flash (or NAS) drive, though, so this may be an option.

CatDV isn't compatible with Yosemite unless you upgrade to version 11, but the pricing is still reasonable for a 'Standard' version; Pro is beyond my threshold in terms of price. Server is another mountain in terms of pricing though, and I'm really just a single user.

More to evaluate.