[SMS]

DiMag · Posted: Wed Jun 05, 2013 2:35 pm Post subject: Can SMS be the better NAS?

I wonder: If you can build an SMS-based NAS on a powerful enough hardware platform (including SATA 600, eSATA, USB 3.0, HDMI, a second PCIe GbNIC), and in building this NAS your only constraint as to the number of disks available for the array is the number of SATA interfaces provided by the mobo - today at least 4 and quite possibly 6, which is 2 or 4 more than offered by most budget NAS boxes -, then what is the benefit of buying a NAS by QNAP, Synology or Thecus instead of building your own? They all run the same Linux you run, right? They all depend, for RAID, on mdadm - not any fancy hardware -, right? Granted, their boxes are smaller, neater, and more thermically efficient. But is this worth the overprice? I am asking because I recently made the experience of having to lift data from an array about to get corrupted, and the problem, of course, was a disk which decayed - initially gradually, then suddenly. I thus came to the conclusion that the only money well spent on a NAS is on a good disk.

gerasimos_h · Posted: Wed Jun 05, 2013 5:48 pm Post subject:

Talking over personal experiences, through my work, those NAS ain't provide anything else than a combo/mini design with low power consumption...
The OS included is at their worst for most of them, with XFS mostly (I prefer JFS) and a bad recovery and fsck scripts...

You can't even think to compare a ready NAS with a full machine with full OS installed...
You can only compare a full machine with a rackable RAID storage with similar specs, but you will end up paying triple the price for it, compared to a PC...

I had made tests between freeNAS and SMS (SMB, AFP) while back on a LACIE rackable NAS and SMS was faster, a full OS was faster than a minimal NAS distribution, imagine that, and that NAS still runs SMS as I write...

I'm not going to mention those boards that claim to have a hardware RAID, but it's a fake raid actually...

In a conclusion it's all about space and money, if you don't have the space and want a simple backup storage buy a ready NAS...
If you want a production RAID, because RAIDs are for production and not for backup, build a power full tower or buy a RAID storage...
And I repeat RAID are not a backup solution, if you want a backup as the word states, you need to have files in two or more different places (physically)...
People tend to confuse that, and buy expensive RAID storages even to work on them, until they realize it the hard way, and that's loosing valuable data.

As for the disks, if you can afford a server grade disks, speaking for WD, WD has some RE and now some NAS (red ones) go for it, if you can't afford them go for black or blue...
Stay way from greens on all brands, and generally avoid them completely even for the cheapest/useless machine...

gerasimos_h

DiMag · Posted: Thu Jun 06, 2013 9:19 pm Post subject:

Let us stay on the NAS/Raid issue. I am (still!) rebuilding my old file structure after having mdadm-assembled the old disks on SMS. My issue is, speed. It is way TOO slow. I knew it would be so, and in order to avoid it I nfs exported the relevant directories on the rebuilt NAS then mounted them on SMS and copied form local directory to local directory. Maximum speed = 27 MB/s. Way too slow for a total of close to 4TB of files. I wonder ---

1. Is there a file system related bottleneck on the rebuilt NAS? It is a QNAP TS-219P (2 bay), ext4. The disks are two WD Reds 3.0TB each. Raid 0. I did not do the formatting, QNAP did. (The network infrastructure is Gb/Cat5e, Linksys switches. Guess it cannot be improved.)

2. Why don't I lift the WD Reds from QNAP and plug them into the SATA ports of the SMS, assemble the new array created on them and mount it locally, and then do a local copy but this time internally SATA to SATA?

gerasimos_h · Posted: Thu Jun 06, 2013 10:27 pm Post subject:

1. I haven't been able to see the LAN gigabit manufacture of the QNAP, but if any of both machines have a realtek ethernet might be the issue, those rl8168, rl8169 are way too slow...
Switch make a difference too on that matter...
Another issue could be the hardware on QNAP...

2. I see that as the better and faster solution, and time is important when it comes to recovery.

gerasimos_h