I installed ntfsprogs on my Debian desktop because I have a Windows partition that I'd like to create an image of on my NAS. I ran ntfsclone with the --save-image option and directed it to place the output in an NFS share to my NAS. I started it last night and it's almost 60% of the way finished.
My lessons learned are as follows:
- Software RAID sucks. I should probably spring for a decent hardware RAID controller.
- Consumer hard disks also suck for large file copies like this one. Those cheap Western Digital disks in my NAS may have seemed like a great deal, but they just don't compare to higher-end SCSI disks. The IO Wait is what's causing it to take so long. It was over 50% when I last looked at it on the NAS.
I should really invest in better equipment at home :)
Update: The ntfsclone imaging finally finished. It turns out that I may have tracked down another culprit relating to the slow file transfer and the high iowait. I have a 3-disk RAID 5 array in my Openfiler NAS. Running mdadm -D /dev/md0 showed that one of the disks was faulty. I rebooted the NAS and re-added that disk to the RAID array. Right now it is in the process of rebuilding, so I'll have to wait a while to see how that goes. Even if it comes back online okay, I'll still probably order an extra disk to add to the array as a spare.
Software RAID in Linux is actually pretty good and is nice and flexible. I've been using it for a very long time. On some very large arrays as well.
ReplyDeleteWhat I do avoid is any fake-RAID stuff that comes on most of the motherboard's chipsets (NVRAID, etc).
Cheap SATA disks tend to time-out rather then report an error back, which can lead to hangs / or disks dropping out of the array all the time. Server grade SATA drives have the TLER set and perform much better.
I absolutely agree with you on the fake-RAID stuff. I avoid using that like the plague.
DeleteSaying software RAID "sucks" was a bit harsh on my part. What I meant is that it doesn't really compare to a decent hardware RAID controller for performance. Being able to offload some processing to the RAID controller is a big plus, but of course, I'm cheap (hence my running consumer grade hard disks).
And I did get that faulty disk replaced. It was developing bad sectors like crazy, so I'm not surprised that it failed when it did.
I have also since parted ways with OpenFiler. As much as I thought I just wanted to have an "appliance" type NAS, I ended up just loading Debian stable and configuring it to be my NAS.