I’m only getting about 3-5, max 10MB/s on writes using RAID 5.
I don’t think the 500MHZ internal processor has nearly enough HP to do RAID 5. This device is sold as a being able to be used as backups – as one primary function – backups are “write many, read little”. Writes have to be fast. I had it copying 660G from another disk and it took over 2 hours to get to ~ `150-200G.’ That’s terrible! Using the same setup but doing the RAID 5 on my host (using the linux md0 driver with 4 SATA HD’s) I can get around 100MB/s on writes.
I don’t want to use RAID0 for this – I’d like it to be ‘stable’ storage. But I don’t want to use RAID1, since I get no stripping, and 1 disk’s BW is just too slow for my usage.
(my home linux partition is on a 6-disk RAID5 w/HW assist and gets 200-300MB/s writes and 300-500MB/s reads).
I bought this unit because it claimed it was fast:
“High-speed access, Ethernet connectivity - Provides data transfer rates up to 1000 Mbit/s when used in a GigE network.Gigabit networking and transfer rates are five to six times faster than other network storage systems. This performance is comparable to USB 2.0 direct-attached storage.”
So the only way it has a hope of speed (w/some safety) would be RAID0+1. The CPU doesn’t have to calculate parity. Mirroring writes are almost as fast as single device writes and reads are usually faster (since you can read whichever copy is available 1st), combine that with striping 2 of them – that should give the best speed for this device (apart from 4-disk RAID0, which is ok for a workstation, using it for local working space but not a shared-space file-server that you want to be a source of reliability).
If we’re lucky the 0+1 mode is already built into the driver, but if not, then a simple recompile?
As for the mount options – how can I specify the mount options on the ext3 mount?
You left off two important options: ‘user_xattr’ and ‘acl’. You support joining the device to an NT4 domain, but you don’t support file acls!? That’s no good. Samba supports NT acls if the underlying file system supports them (or, I think it might be able to emulate them, but I’m not sure how well that works). I know it works great with ‘xfs’ – I’m really sad you didn’t use ‘xfs’ – as it’s the best choice for large file systems to stream media. It even has a defragmenter, something ext3 doesn’t have! I’d also prefer ext3’s “journal=writeback” for my usage AND I’d think most people would prefer ext3 to be mounted with ‘noatime’. It’s another performance drag.
So can we get a patch to enable RAID 1+0 and some way to set the mount options? I don’t care if I have to ‘ssh’ into the box to do it, but as it is now, the entire volumen (all in 1 volume) is mounted before I can log in, and there doesn’t appear to be anyway to unmount and remount it. without writing my own ROM update…which I really wouldn’t feel very confident about doing.