MP 1,1-5,1 First gen apple raid card, slowest raid ever...

[MrVitalic]

Hi! I had the wonderful idea of purchasing a first gen apple raid card for my macpro 1.1 server project (running 10.7.5 server). The raid card have a dead battery atm, but I ordered a replacement cell. From the two sas drive I ordered, only one worked (seagate constellation es 2tb). I ordered two more sas drive but in the mean time, I tried a raid 5 with miss matched drive (3 drive, one sas, two sata). I get a ridiculous 15mb/s write and 35mb/s read.

Question is:

1: with best case scenario ( 3 x 2tb sas drive) , what would be the speed of a raid 5 on this set-up ?
2: Is this thing slowed to a crawl without a cache battery ? (the raid card)
3: I love the raid utility, does lsi or atto integrate with this utility? (I have a rocket raid on pcix that use a browser and I would prefer the raid utility)

Thx. I know its a old school set-up...

 

[Pval]

I got two Pro's with the raid-card, it's only developed for redundancy, not speed. The slots are SATA 2 (2.0? not sure), 300MB/s max theoretical throughput and controlled by either the onboard SATA controller or the raid-card, so probably some logic there that's also keeping things down.

Blackmagic reports ~42MB/s writes and ~250MB/s reads on a 4 disk RAID5 volume on a dual 2,93GHz, 48Gb ram, SSD boot/system, running OSX Sierra.

I bought new batteries too, but they fail quickly, unless you have the power on 24/7/365. In hindsight, I'd probably be better off with a UPS, which is probably cheaper too.
I'm moving to a Synology for storage now and for speed use various SSDs installed for speed. Check the SSD topic.

 

[AidenShaw]

In hindsight, I'd probably be better off with a UPS, which is probably cheaper too.

Most RAID cards with BBWC (battery-backed write cache) require the on-card battery to enable write-back caching. This is to protect your data - unless the RAID card sees a local battery it won't enable write-back caching. The card won't be able to see that you have a UPS, and won't let you be stupid. (Or, it might bury the option deep in some advanced menus.)

Current RAID controllers on commodity x64 servers usually have a dual-mode cache backup. There is a battery (or a super-capacitor) but the card also has a flash store as big as the cache.

When the power drops - the battery is there to provide power for long enough to copy the DRAM cache data to the flash.

If the battery directly powers the cache, you have to get the power back within the hours or few days that the battery runs - otherwise all of your parity raid volumes are gone. If the battery just moves the data to flash - there's no time limit.

I also agree that the NAS boxes are a good option (although I on the QNAP team, not Synology). I don't like that NAS is usually crippled at 1 GBps, whereas a SAS cable is about 5 GBps.

 

[MrVitalic]

Blackmagic reports ~42MB/s writes and ~250MB/s reads on a 4 disk RAID5 volume on a dual 2,93GHz, 48Gb ram, SSD boot/system, running OSX Sierra.

If the battery directly powers the cache, you have to get the power back within the hours or few days that the battery runs - otherwise all of your parity raid volumes are gone. If the battery just moves the data to flash - there's no time limit.

I also agree that the NAS boxes are a good option (although I on the QNAP team, not Synology). I don't like that NAS is usually crippled at 1 GBps, whereas a SAS cable is about 5 GBps.

Ok thx for the info. This is my first attempt at a real raid (not playing around with ssd in software raid 0). My initial goal was to make a nas out of my macpro with a weekly backup to a single 6tb drive (located in the optical bay). To maintain the health of the battery, I was planning to use automator to start the mac every week, then shut down when the battery is fully charged. I may have taken the wrong road with this card, as I dont need a battery backup...The speed reported by Pval are not astonishing but I'l be ok with these. The main os is on a pcie ssd. If the apple raid card doesnt work in the end, I'l move to another set-up. Thx guy!