very poor write performance from u160 scsi drives

lemonlime

Hi, this is my first post here, lots of great info!

I purchased some scsi drives on ebay to play around with, and I'm having some issues relating to write performance.

Here is the scsi specs:

1x Quantum Atlas IV 9.1GB 7200RPM U160 - SCSI ID 0
2x Quantum Atlas 10KII 18.2GB 10000RPM U160 - SCSI ID 4,8
Adaptec 19160 32bit PCI adapter

The system consists of:
Tyan Tiger MPX S2466
2x Athlon MP 1800+
1GB PC2100 Registered DDR


I also have an adaptec 29160N, but I havent had a chance to swap it yet.

I get pretty decent read speeds in atto on all the drives (although I still think they should be higher), however write performance is terrible. It starts at under 500kb/s and peaks out at less than 4mb/s. On the 7200rpm drive, I get read rates of about 25mb (which should still probably be a little higher). I have the two 10KII drives setup as a dynamic striped volume, and I'm peaking the reads out at 60mb/s, and the writes top out at less than 10mb/s.

Any ideas?

I noticed that there were a lot of possible jumper combinations for the drives, however I could not find much information on the different options. I also found it odd that I tried to set the scsi IDs to 0,1,2 and got 0,4,8. All jumper pins (on front and rear) are not shorted with the exception of what I believed to be the ID selection pins. Does anyone know where I could find a correct pin diagram for these quantum drives?

Any help would be much appreciated

Thanks,
Mike

primesuspect

Welcome to short-media

I was having a similar problem a few months ago: http://www.short-media.com/forum/showthread.php?t=8932

I'm not sure if you're having the same issue, but it's a start until the real storage gurus get here

Tex

On those old drives thats probably about right for the reads. One newer drive will just chew those old ones up and spit it out. And they are quieter and cooler running to boot. You can get used u320 Atlas 10k IV's that are less then a year old that hit 73,000 on reads and about 70,000 on writes.

Verify you have write caching enabled in the device manager for the drives first.

Then make sure all the drives are dynamic. I saw you had some in software raid but you need to convert them all to dynamic to get them to score well on ATTO or to copy fast from drive to drive due to some problems on ntfs/scsi on win2k and xp if you were running other drives also

Tex

lemonlime

I tried to convert to dynamic disks, and my atto results were the same. (I am using windows 2003 server enterprise ed, not sure if this issue has been resolved in this O/S).. Write Cache was already enabled on all three drives, however the 'advanced performance' option under that same section was not. After enabling that option, my atto write scores went up drastically.

On the 10KII drives: 23M write, 47M read
On the Atlas IV: 20M write/20M read

The 10KII's read speed always seems to be double the write. Not sure if this is normal. Is it safe to have this 'advanced performance' option enabled?

Do these atto scores look about right for these drives?

Thanks,
Mike

Tex

Don't see the atto results but... Win2k3 has a better solution and I only wish I had that info before you converted to dynamic disks because its a bitch to convert back.

The place to check is in device manager under the disk drive itself beneath the bvox for "enable write cahceing" is a new one not in XP called "advanced performance" or something. Make sure its checked.

The 10k II writes should probably be much closer to the reads but to be honest I am surprised it hit 47,000 on reads as i thought they topped out closer to low 40's. If that mod I mentioned gets the writes into the 40's your doing great. The atlas IV's are much older then anything in the 10k series and I figured mid 20's was max. 20's might be right on. You can check the specs on the maxtor site

Tex

lemonlime

Yep, those high 47,000 scores was with the 'advanced performance' option turned on. In actual fact, the reads were a bit higher before I converted to dynamic disks. I'm going to play around with it a bit more and see if I can get those writes up any higher.

Do you have any newer scsi drives for sale Tex? 18.2GB models are fine, or 36GB.. they do not have to be large, but preferably something a little quicker with more cache memory.?

Thanks,
Mike

TheBaron

Tex gets everything off ebay, I guarantee you he'll point you in that direction

Tex

I have some 15k Fuji drives in 18 and 36gb for sale but the best deal going performance wise and price wise is the Atlas 10k IV's. I have six right now but I have Oracle data bases on them on Linux and it would be a pain to replace them. I buy stuff from several sources including ebay, and basicaly mark it up 15 to 20 percent but... on ebay your lucky to get a NON DOA warranty. I only sell stuff in the forums I have used for 30 days or more and tested extensivley. I do have a reputation to maintain and I dare say you can't find anyone that says I screwed them. With my gear I guarantee your happy or your money back no matter what. If you say.. "Tex the drives are nice but they don't match the color of my bathroom curtains". I say send them back and you eat shipping costs only ( I do reserve the right to roll my eyes and give one long sigh....) (grin)

Many here including mods or admins like dan (shorty) prime, mediaman among the mods know me and trust me to get drives or controllers. eBay is a GREAT place if your careful and IF you can afford to get jacked just in case. I RARELY get screwed on eBay but I'm very careful. I can sell ya stuff direct with my "TEX" no questions asked guarantee or I will help you find gear and tell you secrets of how to bid and save money on eBay if your willing to take the loss if its junk. I will ALWAYS help anyone from this forum find the best deal on ebay or other sources, whether its drives, controllers, MB's or cpu's..... I only have a couple 18gb drives left. Most are 36gb drives. I buy stuff I use internaly on my network and then sell. I never ever buy stuff myself I don't intend to use unless its new. Like I still have some sca and u160 hd68 hot swap mobile racks left when I was buying them by the case....

But the coolest deal going on used drives like I said considering price and performance is the Atlas 10k IV's. Many on ebay sorta uhhh..... misrepresent the old drives that are Atlas IV's and run at 10k rpm as the newer Atlas 10k IV's. Only buy u320 drives and that keeps you out of trouble. The slowest u320 drives made are still a little faster then your drives. Each generation of scsi drives jumps about 20 to 35 percent in performance. So the newer the drives the better. Right now company's are swapping from 18 and 36gb to 70+ gb drives and you can get many nice 36gb drives very reasonable used. A really fast u320 36gb 10k drive should run ya about 60 to 70 bucks on average and hit over 70,000 on atto.

Tex

lemonlime

Thanks for all the info Tex.

How are the Maxtor 15k series u320 drives? is the I/O performance much better than the 10k IV drives? I've seen some 36gb 15k drives that are reasonably priced, although more than the 10kIV drives, thats for sure.

Tex

you will never be able to feel any differance in a desktop type PC between the u320 10k IV's and 15k IV's. The specs and performance is very close when used in a desktop environment but in a server/multi-user environment the lower latency of the 15k really shows an advantage. The STR and access times, amount of cache and stuff is almost equal between the two. The 15k has a very slight edge in str but not enough to matter in a desktop PC. You want more drives not a single faster drive. The key with scsi is it can read and write to multiple drives at the same time basicaly. So you want to try and divid ethe data across the drives. OS on one. Temp files on another swap space on another etc.... its better to have say four 18gb drives to work off then one 73gb if you get my drift here. Or three 36gb.

My Athlon 64 has a lsi u320 controller and three fuji 15k drives. One 18gb and a pair of 36gb as an example. And I wish it had a couple more... See I'm a very very sick pupy...

Tex