I'm thinking of deploying a RN204 and I won't need all four bays for storage (casual storage - media files). Worse case (for the foreseeable future) would be two. So I'm wondering what are the up and down sides of using a SSD for Drive 1 (the boot drive). I have a Samsung SSD Pro (10 year warranty) that I could use.
I'm presuming it would boot and perform OS functions somewhat faster. My data drive(s) if created as a separate volume would be more independent. Such as they could be installed and work in a new installation? Within the relatively same release/hardware. Way back when I installed a SSD and played around and wasn't overly impressed with the enhanced performance so I'm wondering what if anything has changed.
The OS is on a RAID-1 array that uses all the disks. There's no dedicated boot disk.
For network performance gigabit ethernet would be the bottleneck rather than the disk speed at least with large sequential files. SSDs provide a great benefit with read/writes that are more "random" in nature. With SSDs performance transferring a huge number of small files should be greatly improved.
I realize there is no boot drive per se. Although I believe the NAS would be functional with just the SSD drive if I was to remove the other data drives. And I could place the two "data" drives into a similar NAS and access them? I guess you are saying each drive has a copy of the OS and no drive is unique as far as booting the system?
To the point if I pulled the SSD drive (assuming it was the first installed) would the NAS still boot? Would the volume I created on the two "data" drives be accessible? I"m presuming they wouldn't be... However if only the SSD drive was installed it would at least boot and I could access the NAS minus the "data" drives of course.
Now the logic (if there is any) behind the questions is...
Could I remove the two "data" drives from the NAS and it would still be accessible and configured. I could reconfigure/remove the data drives and go from there?
Could I move the "data" drives to another NAS and have them be accessible?
I realize there is no boot drive per se. Although I believe the NAS would be functional with just the SSD drive if I was to remove the other data drives. And I could place the two "data" drives into a similar NAS and access them?
Yes
CharlesR wrote:
I guess you are saying each drive has a copy of the OS and no drive is unique as far as booting the system?
Correct. You'd be limited by the speed of the slowest disk, so using the SSD alongside hard disks in the one system wouldn't make much difference to boot times.
To the point if I pulled the SSD drive (assuming it was the first installed) would the NAS still boot?
Yes
CharlesR wrote:
Would the volume I created on the two "data" drives be accessible?
Yes. The OS is in RAID-1 across all the disks and the volume on the hard disks would be accessible. It would only be if you were say using e.g. a RAID-5 volume using the SSD and the two hard disks and had the SSD and another disk missing/with problems of some sort that you wouldn't be able to access the volume.
CharlesR wrote:
However if only the SSD drive was installed it would at least boot and I could access the NAS minus the "data" drives of course.
Could I remove the two "data" drives from the NAS and it would still be accessible and configured. I could reconfigure/remove the data drives and go from there?
You would see that the disks were marked as dead. Though there is an option now to export the volume, I believe.
Could I move the "data" drives to another NAS and have them be accessible?
Yes. They would need to be the only disks installed and the destination system would also need to be an OS6 system. It would be advisable to update the destination system to the same firmware (or newer) using a scratch disk before moving the disks across. The NAS would recognise that the SSD is missing.
I guess you are saying each drive has a copy of the OS and no drive is unique as far as booting the system?
Correct. You'd be limited by the speed of the slowest disk, so using the SSD alongside hard disks in the one system wouldn't make much difference to boot times.
That seems a bit off. Writes certainly are limited by the speed of the slowest disk, but read speed is determined by whatever drive the NAS happens to pick for reading. This is RAID-1 mirroring, not RAID-5.
Though it will boot from any single drive, I think there is likely an order, and you might be able to bias the boot choice (at least) by picking the right slot for the SSD.
Well it would likely pick different disks at different times to read off I would think. So it may be quicker sometimes, but not always. I haven't tested this though.
I guess I have wondered about this since using ReadyNAS. I (mistakenly) think of the NAS running via a typical OS where there is a boot drive/partition. Rather the OS is written to each drive with some degree of redundancy. Which allows each drive to be accessed if booted by itself? Further if the drive isn't part of a RAID the data (partition/volume) would be accessible?
If the NAS continually reads/writes to each OS partition I can see having only one drive being considerably faster doesn't offering any advantages. My thought process was if the OS is one drive dependent and I'm not needing one for storage... why not use a SSD as the "boot" drive. They are fast, cheap and offer long warranties nowadays.
Yes, if you had a single disk data volume then you would only need that disk to access the data volume. Of course if that disk failed then you would be facing catastrophic data loss if you don't have a backup.
The root volume is too important to store on just the one disk.
I guess I have wondered about this since using ReadyNAS. I (mistakenly) think of the NAS running via a typical OS where there is a boot drive/partition. Rather the OS is written to each drive with some degree of redundancy. Which allows each drive to be accessed if booted by itself? Further if the drive isn't part of a RAID the data (partition/volume) would be accessible?
The OS partitions on each disk are set up as a RAID-1 array. If you have a 4 disk array, then you have triple redundancy (that is, the OS partition can still be read/booted even if 3 drives fail).
There are of course other ways it could have been done.
Makes perfect sense to have the OS redundant (via the other drives) and one of the advantages over a typical OS. My data is "casual" as in there will always be an offline backup and if it's not availablle for a period of time that's fine. Why RAID has little interest for me as far as data.
Bottom line I can see why using a SSD (for one drive) has no advantages. Now I believe some NAS vendors will use it as a caching drive and that might be a different story. I presume the RN204 doesn't feature such...
Worth to mention that a Netgear ReadyDATA appliances (which use ZFS that provides CoW, Deduplication, Compression, ZIL and L2ARC caches generally deployed on SSD), with respect to ReadyNAS appliances (which use BTRFS), do not recognize non-Netgear marked SAS/SATA disks so when you insert a non-Netgear disk, the ReadyDATA dashboard displays the error message "Disk is not signed by NETGEAR". A ReadyDATA appliance recognizes only disks directly/undirectly provided (and marked=signed) by Netgear through they Disk Packs.
