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CentOS4 ok on Dell cerc sata raid ?
by Francois Caen 17 Apr '05

17 Apr '05

Hello, There's been a lot of talk lately about raid controllers :-) I'm thinking about buying a Dell Poweredge with the Dell CERC SATA RAID Controller, 64MB Cache. It'll be either a P4 or a 64bit Xeon. Does CentOS4 recognize these controllers fine? Any extra driver needs to be installed? Thanks, Francois

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Test kernel for a certain feature
by Mário Gamito 16 Apr '05

16 Apr '05

Hi, Is there a command one can issue to check if the kernel supports a certain feature ? Let's say, for instance, Appletalk, or NTFS. Whatever... Warm Regards, Mário Gamito

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Serial ATA hardware raid.
by Franki 16 Apr '05

16 Apr '05

Hi everyone, I'm looking into setting up a SATA hardware raid, probably 5 to use with CentOS 4. I chose hardware raid over software mostly because I like the fact that the raid is transparent to the OS. Does anyone know of any SATA controllers that are well tested for this sort of usage? From what I can tell from googling, this is more or less where RHEL stands: Red Hat Enterprise Linux version 3 and the current version of Fedora support the following SATA chipsets: Intel's ICH5 SATA chipset Silicon Image's SATA chipset Does CentOS4 add anything to this as it is based on 2.6 kernel? My question upon reading what I found on Google, is if it is true hardware raid, shouldn't the OS not be able to tell it's raid at all? I'm assuming that the chipsets listed above are driver based hardware raid? what I am after is a raid array based on true hardware raid such that the OS see's just one drive, and the hardware firmware handles any mirror/striping. Any suggestions? regards Franki

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Re: [CentOS] Serial ATA hardware raid.
by Bryan J. Smith 16 Apr '05

16 Apr '05

From: Franki > After abit of searching, > I found a 4 port 8506 for retail $480 here: BTW, when I was estimating prices earlier, I was using US$. > For the record, this machine is to replace a web server with about 60+ domains hosted, I've been maintaining Linux DNS/SMTP servers since just before Apache surfaced, adding CERN httpd and the "patchy." But the majority of my Linux deployment has been for file servers - especially NFS as of 1999. I still prefer Fujitsu SPARC/Solaris and, even more so, NetApp filers as NFS/SMB plarforms, but throwing around TBph is typical. > some of which get allot of hits, > most are dynamic (Perl/PHP/Java) and the > server runs local MySQL/PostgreSQL as well. I feel very strongly about using RAID-0+1 in this configuration if you can afford to reduce your effective storage by 33% over RAID-5. But the choice is yours. You're not going to make a massive hit since CPU and network is more important. But you should still segment network and storage with an AMD8131 HyperTransport tunnel that provides seperate PCI-X channels for each. And don't skimp on the NIC - get something with at least 256KB SRAM receive cache. > I don't think speed is as important as redundancy, RAID-0+1 means you could possibly lose 2 discs and be okay, although there's no guarantee after losing 1. The other thing 3Ware does is read interleaving between the two mirrors. > but having said that, for future proofing, > I'd like to get a good performer as well. 3Ware's ASIC compared to a Microcontroller is like comparing a layer-2 ASIC+SRAM switch to a PC CPU+DRAM that does switching/routing. The ASIC can do it much faster, although the PC can buffer more. So it depends if you're just throwing data around like layer-2 switching (switching RAID-0, 1, 0+1 reads/writes), or if you are calculating dynamic routes in non-real-time (like RAID-5 XORs for parity). That's why 3Ware calls it a "storage switch." Of course if you have a 9500, it has DRAM too, so it's like having a layer-3 switch (that can route too). And without the inefficiency of the PC interconnect. > Which brings up another question, > I was looking at populating this thing > with 10,000 RPM 8MB cache 40gig (roughly) drives, > but the only drives I see in my pricelists that > match those specs are Western Digital Wd360GB's > and I generally have stayed away from WD drives in the > past due to dodgy standards implimentation > and the problems that can cause with Linux, First, other than Maxtor, Seagate and Hitachi, no one makes their own drives. WD taps the first and last for many, and Maxtor's approch is different than Seagate and Hitachi (I'll send you a link to any explaination). Secondly, the ATA drives *never* talk to the system, only the 3Ware ASIC. And unlike GPL Linux, 3Ware can get proprietary command set info from vendors. I have *never* had a "DMA timeout" in the history of my 6-year 3Ware usage. > should I continue to stay away? WD's 10,000rpm drives come off the same "enterprise" line as Hitachi's SCSI/SATA. They are not commodity at all. Hitachi and Seagate have dedicated "enterprise" lines for some SCSI/SATA, and then "commodity" lines for SCSI/SATA/ATA. Maxtor has only one line and then tests for tolerance and those that rate high are then declared "enterprise" with a 3-5 year warranty. > Actually, now that I think about it, > I guess 10,000 rpm drives with raid is probably over kill for my usage, Actually, since you are more concerned with latency in your application, then a faster spindle is better. In reality, the higher the density, typically the higher the DTR. So it is very common to see lower density or 1-gen back of higher spindles have a *lower* DTR than a lower spindle. > but they are pretty cheap anyway, (149 AUD each) but > if WD are still dodgy I have WD 40, 80 and 160 "consumer" ATA/SATA drives that give some chipsets fits under Linux, but 0 issues on a 3Ware card. > then I'd probably go for 7200rpm seagates > as I can get the 8MB 80gig 7200rpm drives for $85 AUD. Seagate is the only manufacture giving 3-5 year warranties on their "consumer" drives instead of 1-3. Yes, they cost 10-20% more than Maxtor/WD, but that's piece-of-mind IMHO. The "sweet spot" right now seems to be 200GB (160-250GB) for size, density (DTR performance) and price (sub-US$100). (4) 200GB = 400GB effective RAID-0+1. > Are Western Digitals still dodgy? All "integrated drive electronics" (IDE) drives via Advanced Technology (AT) Attachment (ATA) seem to do a poor job of following ATA-5 and ATA-6 specs. But with 3Ware, I've yet to have an issue. I even have 80GB WDs on old 3Ware 6000 series cards with 3-year-old firmware 6.9 that don't have an issue. BTW, 40C is the maximum ambient temperature a "consumer" SCSI/SATA/ATA drive should be exposed to. Drive life dives off if they run hotter. So consider getting a hot-swap enlosure that fits in a 3x5.25" bay that has 5 bays. They run $150.

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CentOS4 Loop at shutdown
by Collins Richey 16 Apr '05

16 Apr '05

Has anyone else encountered a loop and failure to shutdown on CentOS4? This has occurred twice in the past month, but unfortunately I failed to write down the looping messages. The only relevant problems I found via Google reference raid controllers, and I have POI (plain ol' IDE). Doh! Obviously I wuill need to record the errors. My environment is run-level 5 with GDM, but I use IceWm instead of one of the more common choices. IceWm shuts down cleanly. The loop occurs after selecting Shutdown from the GDM login panel. Errata are current as of last night. -- Collins When I saw the Iraqi people voting three weeks ago, 8 million of them, it was the start of a new Arab world.... The Berlin Wall has fallen. - Lebanese Druze leader Walid Jumblatt

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Document Management System
by Joao Medeiros 16 Apr '05

16 Apr '05

Hi all, I was wondering if someone can give me some pointers to a good Document Management System. I've been using Knowledge Tree for a while and just wondering if there is something a bit more robust. I'm archiving technical specs, functional documents, etc... TIA, Joao João Medeiros Linux User 381318

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RE: Older 3ware controller, was: [CentOS] Serial ATA hardware raid.
by Bryan J. Smith 16 Apr '05

16 Apr '05

From: Harald Finnås > You seem to know what you're talking about, Seems v. Knows is a whole new ballgame. But I have been deploying SCSI on Linux since 1993 (Advansys, now owned by LSI, was the first vendor to formally support Linux), SCSI RAID on Linux since 1997 (large ICP-Vortex), through 3Ware's original FPGA ASIC designs in the AccelATA and Escalade 5000 series in 1999+. For a more "concept-level" dissertation on: - Software RAID via OS LDM/LVM - Fake/Free RAID (FRAID) "dumb cards" - Buffering Microcontroller+DRAM intelligent cards - Non-blocking ASIC+SRAM intelligent cards see my article "Dissecting ATA RAID Options in Sys Admin magazine (http://www.samag.com) 2004 April. It's now dated, but the concepts still apply. > One of my friends called me the other day regarding problems with centos > installation on 3ware 7810-8 controller. I have several of that, same model -- 64-bit, 1MB SRAM > According to him the driver loads just fine, he can see AND partition the drive from the console, > but the installation program doesn't seem to want to use the array. The system doesn't dual-boot with Windows, does it? If so, it could be a LDM Disk Label (Dynamic Disc) which kernel 2.4.x supports, but Red Hat Anaconda (which uses GNU Parted/GRUB) does not. Also, consider upgrading to the latest firmware. If you're booting RH3+ (RHL8/9/FC1, RHEL3), you should be at least release 7.7.x. Otherwise there might be driver-firmware interaction issues. > He says it works like a charm on > mdk 9.2 beta. > Any tips? Boot with "linux expert" and hit Alt-F2 and run "fdisk -l /dev/sda". > I haven't looked into the problem yet, > and I don't even know what this old controller is. :) _All_ Escalade 7000/8000 series controllers use the same 64-bit ASIC, FPGA (field programmable) ATA logic and firmware. This includes a 7.5 (was it?) release that added LBA48 (ATA-6) addressing and UDMA Mode 6 (U133) speed support. Again., getting to 7.7.x should be a top priority - the RH3 and, especially, RH4 kernels have drivers that match these much newer 3Ware firmware-driver-3DM releaases. FYI: For reference: 7400/7800 = 33PCI64 full-length, 64-bit ASIC, 1MB SRAM, 4/8 channel 7410/7810 = as 7400/7800 but *half*-length 7450/7850 = as 7410/7810 but *2MB* 0 wait state SRAM 7500-4/8 = 7450/7850 merely renamed 7500-12 = as 7500-4/8, but with *4MB* SRAM and 12 channels 7506-x = as 7500-x, but 66PCI64 interface (ASIC clock doubled)

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Re: [CentOS] Serial ATA hardware raid.
by Franki 15 Apr '05

15 Apr '05

Jonathan wrote: > Franki: > > Can't speak for all of them, but the IDE 160s I bought failed me pretty > hard (2 of 6 failed within a year). The 250s Sata 8ms I bought for a > NAS application have been rock solid. > > Seems inconsistent, but in general the WD Sata drives I have are pretty > solid. > > Jonathan I don't understand, aren't they more or less the same drive with a different PCB on the back? I'm just remembering all the problems I had several years back when I was running RH4-6.2 on WD drives. I would imagine that with striping, the 8MB 7200 drives would be good enough, and besides, it's not like I can't upgrade later. The 10,000rpm drives have me alittle worried about heat and longevity anyway. Thanks for all your help guys, I'm amazed at the wealth of knowledge on this list. regards Frank

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Re: [CentOS] Serial ATA hardware raid.
by Bryan J. Smith 15 Apr '05

15 Apr '05

From: Franki > The 3ware 9500 goes for $1023 AUD. > once I add some fast drives to that this thing is starting to look like an expensive upgrade. RAID-5 is only ideal for lots of contiguous reads or disk storage efficiency. If you have more writes, or more random reads, then RAID-0+1 is better. Then the 8506 does nice for less. > My main wholesaler sells Adaptec stuff, I live 5 miles from one of Adaptec's major support centers in the 1,006 acre University of Central Florida Research Park. I know many Adaptec employees. Adaptec still does not officially support Linux for RAID cards, only standard SCSI adapters. And unlike LSI/Symbios, who treats OEM and retail the same (making suppor easier), Adaptec is retail focused, and produces variants for OEMs that are quite compatibility nightmares. > http://www.techbuy.com.au/products/34526/I_OCARDS_HARDDRIVECONTROLLERS/Adda… > For $450 it is a 4 port controller and has onboard 64MB ECC cache. Adaptec's aging 2400A/2800A series are 66-100MHz i960/IOP30x series based on their former DPT acquisition. In fact, before their DPT acquisition, they had virtually *no* i960 or StrongARM solution that worked with Linux. Since then, the support has been varied, although the dpt_i2o driver seems to work with most products. Intel designed I20 for its i960 to make drivers and user-space software more uniform compatible, but only a few vendors (like DPT and LSI) took advantage of it. I used to have DPT and LSI i960 SCSI RAID controllers on Linux, NT, OpenVMS and UNIX on a variety of non-PC platforms like Alpha and MIPS. But, as I mentioned before, the i960/IOP30x is a *massive*slouche* for today's drives. The ones used in the 2400A/2800A series were fine 5 years ago, but don't even bother with the 28x0 and the 24x0's i960 is going to be the bottleneck. And then you have the fact that Adaptec is "hands-off," officially, on the dpt_i2o driver. Get a 3Ware Escalade 8506-4 for about the same price, and either run RAID-5 if you have lots of reads, or RAID-0+1 if you are doing lots of writes (especially random). Yeah, you'll lose a disk in the effective storage for RAID-0+1, but I've yet to see an application where RAID-5 could beat RAID-0+1 on any controller. > But Alexander on the list here said that adaptec is questionable > for Raid cards. The last time I had an Adaptec anything was a 2940UW Scsi controller > and that thing gave me years of good service. Retail, of course. For those of us with OEM versions, Linux compatibility is a nightmare. Why can't Adaptec be like LSI and just have one set of firmware? > Not sure what to chase up now. :-( > Does anyone have any experiance with the above adaptec card? Yes. At RAID-5, it only beats the Escalade 8506 at random writes where the measly 2-4MB SRAM oveflows. But then the Escalade 9500S with 128MB+ of DRAM buffer (in addition to the ASIC+SRAM cache) wipes the floor with it because it doesn't have a 10 year-old i960 behind it. When it comes to non-writes (or RAID-0, 1 or 0+1 non-blocking), its 32-bit blocking/buffering i960 microcontroller+DRAM bottleneck looses badly to the 64-bit non-blocking/caching ASIC+SRAM design of any 3Ware product. And 3Ware writes the GPL drivers in the kernel, which have been included since 2.2.15 (yes, 2.*2*.15). 3Ware's 3DM2 suite is also very nice for user-space monitoring. And yes, you can load 3DM2 from the 9500S download on the older 7000/8000 series (just not the 6000 series). BTW, performance matters *little* if you are putting your storage controller on the same bus as your NIC. Especially if it's a measly, "shared" 33MHz PCI32 bus. You might as well use 2 hard drives in RAID-1 because you're going to saturate it - let alone your GbE is going to be "fighting" it. Get a mainbaord with PCI-X, or at least get a chipset with the GbE on a HyperTransport interconnect or PCIe x1 rail so it's not fighting the storage controller for the PCI bus. Of course most chipset GbE and 99% of GbE cards are poorly designed (8-32KB of SRAM is typical, 64KB is you are lucky), and one should get a GbE card for a server with at least 256KB SRAM.

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Re: [CentOS] Serial ATA hardware raid.
by Bryan J. Smith 15 Apr '05

15 Apr '05

From: Harald Finnås > 3ware (7500, 8500, 9500) is IMHO best bet on all distros 3Ware includes a GPL driver in the stock kernel. Although as with any "intelligent" storage adapter, you should verify the driver, firmware and user-space tools are compatible. I need to get my FAQ out showing 3Ware releases v. Red Hat updates. The 3Ware 7506/8506 are of the same 64-bit ASIC 66MHz PCI64 storage switch. They are non-blocking (like a network switch) thanx to their ASIC+SRAM (static RAM) design and kill at RAID-0, 1 and 0+1. While they are also high performing at RAID-5 reads, the small amount of 2MB (-4, -8) or 4MB (-12) SRAM can overflow on random, RAID-5 writes. The 3Ware 9500S series adds 128MB+ SDRAM to help buffer these overflows. Unlike RAID-0, 1 and 0+1, RAID-3/4/5 are always blocking/buffered I/O, so the ASIC+SRAM design goes from an advantage to a liability. So if your application calls for lots of random writes, either use RAID-0+1 or get a 9500S for $50-200 more. > I also run it on an LSI SATA controller, > but I cannot remember the exact model. > But I can find it if you want to know. :) Unless the model says "X" (for XScale), you don't want it. Pre-XScale (StrongARM lineage) microcontroller+DRAM designs are *dog*slow*. Intel i960 (including IOP30x series) can't push much beyond 60-70MBps. While that was sufficient for yester-year's drives in RAID-3/4/5, it is not today. And blocking/buffered is never ideal for ATA. The StrongARM and, subsequent, superscalar XScale microcontrollers change everything. They can push as little as 200MBps in old designs up to 500MBps in the new IOP32x/33x series. But you'll pay through the nose for the cards, $500+, although they do best even the 3Ware 9500S at RAID-5. Some have RAID-3/4 options that are more ideal than RAID-5 for desktops and NFS servers, respectively. But if you are looking for maximum performance, reliability and compatibility as well as load-balanced reads, RAID-0+1 on a sub-$300 3Ware Escalade 8506-4 (or a -8 for a little more) is pretty much unbeatable. The 9500S is overkill for just RAID-0+1, and if you're doing lots of writes, it's typically going to be faster than any RAID-5 solution. For extreme performance with disk redundancy, consider (2) 3Ware 8506 cards in an Opteron system with an AMD8131 or AMD8132 dual-PCI-X bus HyperTransport Tunnel -- with each card on their own PCI-X bus and then their individual RAID-0+1 volumes in a single LVM2 stripe set (RAID-0). Connected to a GbE in the HyperTransport interconnect or, better yet, a HTX (HyperTransport) 10GbE (just coming out) or InfiniBand (upto 1.8GBps actual performance on HTX) and you're slapping silly anything Intel can offer with either Xeon or Itanium over PCI-X by a factor of 2-3x.

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