Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R (A
Did you ever figure this out? I have the same hardware: Intel DG33TL motherboard with Intel gigabit nic and ICH9R but with Hitachi 1TB drives. I'm getting 2MB/s write speeds. I've tried the zeroing out trick. No luck. Network is fine. Disks are fine, the write at around 50MB/s when formatted with ext3 under Linux. This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R (A
Oh, Jeff's write script gives around 60MB/s IIRC. This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R (A
I used BCwipe to zero the drives. How do you: boot Knoppix again and zero out the start and end sectors manually (erasing all GPT data) ?? thanks This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R (A
Hi, First of all, my apologies for some of my posts appearing 2 or even 3 times here, the forum seems to be acting up, and although I received a Java exception for those double postings and they never appeared yesterday, apparently they still made it through eventually. Back on topic: I fruitlessly tried to extract higher write speeds from the Seagate drives using an Addonics Silicon Image 3124 based SATA controller. I got exactly the same 21 MB/s for each drive (booted from a Knoppix cd). I was planning on contacting Seagate support about this, but in the mean time I absolutely had to start using this system, even if it meant low write speeds. So I installed Solaris on a 1GB CF card and wanted to start configuring ZFS. I noticed that the first SATA disk was still shown with a different label by the format command (see my other post somewhere here). I tried to get rid of all disk labels (unsuccessfully), so I decided to boot Knoppix again and zero out the start and end sectors manually (erasing all GPT data). Back to Solaris. I ran zpool create tank raidz c1t0d0 c1t1d0 c1t2d0 and tried a dd while monitoring with iostat -xn 1 to see the effect of not having a slice as part of the zpool (write cache etc). I was seeing write speeds in excess of 50MB/s per drive! Whoa! I didn't understand this at all, because 5 minutes earlier I couldn't get more than 21MB/s in Linux using block sizes up to 1048576 bytes. How could this be? I decided to destroy the zpool and try to dd from Linux once more. This is when my jaw dropped to the floor: [EMAIL PROTECTED]:~# dd if=/dev/zero of=/dev/sda bs=4096 ^[250916+0 records in 250915+0 records out 1027747840 bytes (1.0 GB) copied, 10.0172 s, 103 MB/s Finally, the write speed one should expect from these drives, according to various reviews around the web. I still get a healthy 52MB/s at the end of the disk: # dd if=/dev/zero of=/dev/sda bs=4096 seek=18300 dd: writing `/dev/sda': No space left on device 143647+0 records in 143646+0 records out 588374016 bytes (588 MB) copied, 11.2223 s, 52.4 MB/s But how is it possible that I didn't get these speeds earlier? This may be part of the explanation: [EMAIL PROTECTED]:~# dd if=/dev/zero of=/dev/sda bs=2048 101909+0 records in 101909+0 records out 208709632 bytes (209 MB) copied, 9.32228 s, 22.4 MB/s Could it be that the firmware in these drives has issues with write requests of 2048 bytes and smaller? There must be more to it though, because I'm absolutely sure that I used larger block sizes when testing with Linux earlier (like 16384, 65536 and 1048576). It's impossible to tell, but maybe there was something fishy going on which was fixed by zero'ing parts of the drives. I absolutely cannot explain it otherwise. Anyway, I'm still not seeing much more than 50MB/s per drive from ZFS, but I suspect the 2048 VS 4096 byte write block size effect may be influencing this. Having a slice as part of the pool earlier perhaps magnified this behavior as well. Caching or swap problems are certainly no issues now. Any thoughts? I certainly want to thank everyone once more for your co-operation! Greetings, Pascal This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
Pascal Vandeputte pascal_vdp at hotmail.com writes: I'm at a loss, I'm thinking about just settling for the 20MB/s write speeds with a 3-drive raidz and enjoy life... As Richard Elling pointed out, the ~10ms per IO operation implies seeking, or hardware/firmware problems. The mere fact you observed a low 27 MB/s sequential write throughput on c1t0d0s0 indicates this is not a ZFS pb. Test other disks, another SATA controller, mobo, BIOS/firmware, etc. As you pointed out, these disks should normally be capable of a 80-90 MB/s write throughput. Like you I would also expect ~100 MB/s writes on a 3-drive raidz pool. As a datapoint, I see 150 MB/s writes on a 4-drive raidz on a similar config (750GB SATA Samsung HD753LJ disks, SB600 AHCI controller, low-end CPU). -marc ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
Thanks, I'll try installing Solaris on a 1GB CF card in an CF-to-IDE adapter, so all disks will then be completely available to ZFS. Then I needn't worry about different size block devices either. I also find it weird that the boot disk is displayed differently from the other two disks if I run the format command... (could be normal though, as I said before I'm new to Solaris) # format Searching for disks...done AVAILABLE DISK SELECTIONS: 0. c1t0d0 DEFAULT cyl 45597 alt 2 hd 255 sec 126 /[EMAIL PROTECTED],0/pci8086,[EMAIL PROTECTED],2/[EMAIL PROTECTED],0 1. c1t1d0 ATA-ST3750330AS-SD15-698.64GB /[EMAIL PROTECTED],0/pci8086,[EMAIL PROTECTED],2/[EMAIL PROTECTED],0 2. c1t2d0 ATA-ST3750330AS-SD15-698.64GB /[EMAIL PROTECTED],0/pci8086,[EMAIL PROTECTED],2/[EMAIL PROTECTED],0 This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
(the lt and gt symbols are filtered by the forum I guess; replaced with minus signs now) # format Searching for disks...done AVAILABLE DISK SELECTIONS: 0. c1t0d0 -DEFAULT cyl 45597 alt 2 hd 255 sec 126- /[EMAIL PROTECTED],0/pci8086,[EMAIL PROTECTED],2/[EMAIL PROTECTED],0 1. c1t1d0 -ATA-ST3750330AS-SD15-698.64GB- /[EMAIL PROTECTED],0/pci8086,[EMAIL PROTECTED],2/[EMAIL PROTECTED],0 2. c1t2d0 -ATA-ST3750330AS-SD15-698.64GB- /[EMAIL PROTECTED],0/pci8086,[EMAIL PROTECTED],2/[EMAIL PROTECTED],0 This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
Great, superb write speeds with a similar setup, my motivation is growing again ;-) It just occurs to me that I have a spare Silicon Image 3124 SATA card lying around. I was postponing testing of these drives on my desktop because it has an Intel ICH9 SATA controller probably quite similar to the ICH9R (RAID support) in my Solaris box, but that 3124 may give completely different results with the Seagates. Test coming up. (the forum seems to be having technical difficulties, I hope my replies end up in the right places...) This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
Thanks a lot for your input, I understand those numbers a lot better now! I'll look deeper into hardware issues. It's a pity that I can't get older BIOS versions flashed. But I've got some other hardware lying around. Someone suggested lowering the 35 iops default, but I can't find any information anywhere on how to accomplish this (not with Google, not in the ZFS Admin guide either). Greetings, Pascal This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
Pascal Vandeputte wrote: Thanks a lot for your input, I understand those numbers a lot better now! I'll look deeper into hardware issues. It's a pity that I can't get older BIOS versions flashed. But I've got some other hardware lying around. Someone suggested lowering the 35 iops default, but I can't find any information anywhere on how to accomplish this (not with Google, not in the ZFS Admin guide either). It is in the Evil Tuning Guide. But don't bother, it won't fix your problem. The evidence suggests you get 10ms response even with only 1 iop queued to the device. -- richard ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
Pascal Vandeputte wrote: I see. I'll only be running a minimal Solaris install with ZFS and samba on this machine, so I wouldn't expect immediate memory issues with 2 gigabytes of RAM. OTOH I read that ZFS is a real memory hog so I'll be careful. Memory usage is completely dependent on the workload. Unless you are doing a *lot* of writes with a slow back end (hmmm) then you should be ok with modest RAM. I've tested swap on a ZFS volume now, it's really easy so I'll try running without swap for some quick performance testing and use swap on ZFS after that. This also takes away my fears about using a swap slice on the CompactFlash card I'll be booting from. To save you some grief, please wait for b88 before swapping to ZFS. Don't worry about swapping on CF. In most cases, you won't be using the swap device for normal operations. You can use the swap -l command to observe the swap device usage. No usage means that you can probably do away with it. If you actually use swap, performance will suck, so buy more RAM. -- richard ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
Bob Friesenhahn wrote: On Sat, 19 Apr 2008, Richard Elling wrote: Don't worry about swapping on CF. In most cases, you won't be using the swap device for normal operations. You can use the swap -l command to observe the swap device usage. No usage means that you can probably do away with it. If you actually use swap, performance will suck, so buy more RAM. I don't agree that if swap is used that performance will necessarily suck. If swap is available, Solaris will mount /tmp there, which helps temporary file performance. It is best to look at system paging (hard faults) while programs are running in order to determine if performance sucks due to inadequate RAM. In many runtime environments, only a small bit of the application address space is ever needed. swapfs is always there. But, IMHO, it is a misnomer because it just uses the virtual memory system. The prevailing method of determining memory shortfall is to observe the page scanner (scan rate, sr). But just for grins, try swap -l on your systems and see if any pages have been used on the swap device. The answer usually surprises ;-) More RAM definitely improves ZFS repeated read performance due to caching in RAM. ZFS gives otherwise unused memory something useful to do. Regardless, with a 64-bit CPU and a 64-bit OS it seems like a crying shame to install less than 4GB of RAM. :-) Yep, or if you do OpenGL stuff, like I've been doing lately, much more RAM :-) -- richard ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
On Sat, Apr 19, 2008 at 10:28:45AM -0700, Richard Elling wrote: Bob Friesenhahn wrote: I don't agree that if swap is used that performance will necessarily suck. If swap is available, Solaris will mount /tmp there, which helps temporary file performance. It is best to look at system paging (hard faults) while programs are running in order to determine if performance sucks due to inadequate RAM. In many runtime environments, only a small bit of the application address space is ever needed. swapfs is always there. But, IMHO, it is a misnomer because it just uses the virtual memory system. Why a misnomer? swap and virtual memory are used as identical terms in many places in Solaris. But since /tmp was mentioned, perhaps you're referring to tmpfs instead of swapfs? -- Darren Dunham [EMAIL PROTECTED] Senior Technical Consultant TAOShttp://www.taos.com/ Got some Dr Pepper? San Francisco, CA bay area This line left intentionally blank to confuse you. ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
On Sun, 20 Apr 2008, A Darren Dunham wrote: I think these paragraphs are referring to two different concepts with swap. Swapfiles or backing store in the first, and virtual memory space in the second. The swap area is mis-named since Solaris never swaps. Some older operating systems would put an entire program in the swap area when the system ran short on memory and would have to swap between programs. Solaris just pages (a virtual memory function) and it is very smart about how and when it does it. Only dirty pages which are not write-mapped to a file in the filesystem need to go in the swap area, and only when the system runs short on RAM. Solaris is a quite-intensely memory-mapped system. The memory mapping allows a huge amount of sharing of shared library files, program text images, and unmodified pages shared after fork(). The end result is a very memory-efficient OS. Now if we could just get ZFS ARC and Gnome Desktop to not use any memory, we would be in nirvana. :-) Bob == Bob Friesenhahn [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer,http://www.GraphicsMagick.org/ ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
Bob Friesenhahn wrote: On Sun, 20 Apr 2008, A Darren Dunham wrote: I think these paragraphs are referring to two different concepts with swap. Swapfiles or backing store in the first, and virtual memory space in the second. The swap area is mis-named since Solaris never swaps. Some older operating systems would put an entire program in the swap area when the system ran short on memory and would have to swap between programs. Solaris just pages (a virtual memory function) and it is very smart about how and when it does it. Only dirty pages which are not write-mapped to a file in the filesystem need to go in the swap area, and only when the system runs short on RAM. that's true most of the time ... unless free memory gets *really* low, then Solaris *does* start to swap (ie page out pages by process). IIRC, the threshold for swapping is minfree (measured in pages), and the value that needs to fall below this threshold is freemem. HTH Michael -- Michael Schuster http://blogs.sun.com/recursion Recursion, n.: see 'Recursion' ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
On Sat, 19 Apr 2008, michael schuster wrote: that's true most of the time ... unless free memory gets *really* low, then Solaris *does* start to swap (ie page out pages by process). IIRC, the threshold for swapping is minfree (measured in pages), and the value that needs to fall below this threshold is freemem. Most people here are likely too young to know what swapping really is. Swapping is not the same as the paging that Solaris does. With swapping the kernel knows that this address region belongs to this process and we are short of RAM so block copy the process to the swap area, and only remember that it exists via the process table. Bob == Bob Friesenhahn [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer,http://www.GraphicsMagick.org/ ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
Thanks for all the replies! Some output from iostat -x 1 while doing a dd of /dev/zero to a file on a raidz of c1t0d0s3, c1t1d0 and c1t2d0 using bs=1048576: extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 0.0 104.00.0 13312.0 4.0 32.0 346.0 100 100 sd1 0.0 104.00.0 13312.0 3.0 32.0 336.4 100 100 sd2 0.0 104.00.0 13312.0 3.0 32.0 336.4 100 100 extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 0.0 104.00.0 13311.5 4.0 32.0 346.0 100 100 sd1 0.0 106.00.0 13567.5 3.0 32.0 330.1 100 100 sd2 0.0 106.00.0 13567.5 3.0 32.0 330.1 100 100 extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 0.0 135.00.0 12619.3 2.6 25.9 211.3 66 100 sd1 0.0 107.00.0 8714.6 1.1 16.3 163.3 38 66 sd2 0.0 101.00.0 8077.0 1.0 14.5 153.5 32 61 extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 1.0 13.08.0 14.5 1.7 0.2 139.9 29 22 sd1 0.06.00.04.0 0.0 0.00.9 0 0 sd2 0.06.00.04.0 0.0 0.00.9 0 0 extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 0.0 77.00.0 9537.9 19.7 0.6 264.5 63 63 sd1 0.0 122.00.0 13833.2 1.7 19.6 174.5 58 63 sd2 0.0 136.00.0 15497.6 1.7 19.6 156.8 59 63 extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 0.0 106.00.0 13567.8 34.0 1.0 330.1 100 100 sd1 0.0 103.00.0 13183.8 3.0 32.0 339.7 100 100 sd2 0.0 97.00.0 12415.8 3.0 32.0 360.7 100 100 extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 0.0 104.00.0 13311.7 34.0 1.0 336.4 100 100 sd1 0.0 83.00.0 10623.8 3.0 32.0 421.6 100 100 sd2 0.0 76.00.0 9727.8 3.0 32.0 460.4 100 100 extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 0.0 104.00.0 13312.7 34.0 1.0 336.4 100 100 sd1 0.0 104.00.0 13312.7 3.0 32.0 336.4 100 100 sd2 0.0 105.00.0 13440.7 3.0 32.0 333.2 100 100 extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 0.0 104.00.0 13311.9 34.0 1.0 336.4 100 100 sd1 0.0 106.00.0 13567.9 3.0 32.0 330.1 100 100 sd2 0.0 105.00.0 13439.9 3.0 32.0 333.2 100 100 extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 0.0 106.00.0 13567.6 34.0 1.0 330.1 100 100 sd1 0.0 106.00.0 13567.6 3.0 32.0 330.1 100 100 sd2 0.0 104.00.0 13311.6 3.0 32.0 336.4 100 100 extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 0.0 120.00.0 14086.7 17.0 18.0 291.6 100 100 sd1 0.0 104.00.0 13311.7 7.8 27.1 336.4 100 100 sd2 0.0 107.00.0 13695.7 7.3 27.7 327.0 100 100 extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 0.0 103.00.0 13185.0 3.0 32.0 339.7 100 100 sd1 0.0 104.00.0 13313.0 3.0 32.0 336.4 100 100 sd2 0.0 104.00.0 13313.0 3.0 32.0 336.4 100 100 extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 0.0 115.00.0 12824.4 3.0 32.0 304.3 100 100 sd1 0.0 131.00.0 14360.3 3.0 32.0 267.1 100 100 sd2 0.0 125.00.0 14104.8 3.0 32.0 279.9 100 100 extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 0.0 99.00.0 12672.9 3.0 32.0 353.4 100 100 sd1 0.0 82.00.0 10496.8 3.0 32.0 426.7 100 100 sd2 0.0 95.00.0 12160.9 3.0 32.0 368.3 100 100 extended device statistics devicer/sw/s kr/s kw/s wait actv svc_t %w %b sd0 0.0 104.00.0 13311.7 3.0 32.0 336.4 100 100 sd1 0.0 103.00.0 13183.7 3.0 32.0 339.7 100 100 sd2 0.0 105.00.0 13439.7 3.0 32.0 333.2 100 100 Similar output when running iostat -xn 1: extended device statistics r/sw/s kr/s kw/s wait actv wsvc_t asvc_t %w %b device 0.0 103.00.0 13184.3 4.0 32.0 38.7
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
On Fri, 18 Apr 2008, Pascal Vandeputte wrote: Thanks for all the replies! Some output from iostat -x 1 while doing a dd of /dev/zero to a file on a raidz of c1t0d0s3, c1t1d0 and c1t2d0 using bs=1048576: [ data removed ] It's all a little fishy, and kw/s doesn't differ much between the drives (but this could be explained as drive(s) with longer wait queues holding back the others I guess?). Your data does strongly support my hypothesis that using a slice on 'sd0' would slow down writes. It may also be that your boot drive is a different type and vintage from the other drives. Testing with output from /dev/zero is not very good since zfs treats blocks of zeros specially. I have found 'iozone' (http://www.iozone.org/) to be quite useful for basic filesystem throughput testing. Hmm, doesn't look like one drive holding back another one, all of them seem to be equally slow at writing. Note that if drives are paired, or raidz requires a write to all drives, then the write rate is necessarily limited to the speed of the slowest device. I suspect that your c1t1d0 and c1t2d0 drives are similar type and vintage whereas the boot drive was delivered with the computer and has different performance characteristics (double wammy). Usually drives delivered with computers are selected by the computer vendor based on lowest cost in order to decrease the cost of the entire computer. SATA drives are cheap this days so perhaps you can find a way to add a fourth drive which is at least as good as the drives you are using for c1t1d0 and c1t2d0. Bob == Bob Friesenhahn [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer,http://www.GraphicsMagick.org/ ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
Hi, Thanks for your input. Unfortunately, all 3 drives are identical Seagate 7200.11 drives which I bought separately and they are attached in no particular order. Thanks about the /dev/zero remark, I didn't know that. From what I've seen this afternoon, I'm starting to suspect a hardware/firmware issue as well. Using Linux I cannot extract more than 24,5 MB/s sequential write performance out of a single drive (writing directly to /dev/sdX, no filesystem overhead). I tried flashing the BIOS to an older version, but that firmware update process fails somehow. Reflashing the newest BIOS still works however. It's a pity that I didn't benchmark before updating the BIOS RAID firmware package. Maybe then I would have gotten decent Windows performance as well. It could even be an issue with the Seagate disks, as there have been problems with SD04 and SD14 firmwares (reported 0MB cache to the system). Mine are SD15 and should be fine though. I'm at a loss, I'm thinking about just settling for the 20MB/s write speeds with a 3-drive raidz and enjoy life... Which leaves me with my other previously asked questions: - does Solaris require a swap space on disk - does Solaris run from a CompactFlash card - does ZFS handle raidz or mirror pools with block devices of a slightly different size or am I risking data loss? Thanks, Pascal This message posted from opensolaris.org ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
On Fri, 18 Apr 2008, Pascal Vandeputte wrote:
- does Solaris require a swap space on disk
No, Solaris does not require a swap space. However you do not have a
lot of memory so when there is not enough virtual memory available,
programs will fail to allocate memory and quit running. There is an
advantage to having a swap area since then Solaris can put rarely used
pages in swap to improve overall performance. The memory can then be
used for useful caching (e.g. ZFS ARC), or for your applications.
In addition to using a dedicated partition, you can use a file on UFS
for swap ('man swap') and ZFS itself is able to support a swap volume.
I don't think that you can put a normal swap file on ZFS so you would
want to use ZFS's built-in support for that.
Bob
==
Bob Friesenhahn
[EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,http://www.GraphicsMagick.org/
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Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R
On Fri, Apr 18, 2008 at 8:28 AM, Bob Friesenhahn [EMAIL PROTECTED] wrote: On Fri, 18 Apr 2008, Pascal Vandeputte wrote: Thanks for all the replies! Some output from iostat -x 1 while doing a dd of /dev/zero to a file on a raidz of c1t0d0s3, c1t1d0 and c1t2d0 using bs=1048576: [ data removed ] It's all a little fishy, and kw/s doesn't differ much between the drives (but this could be explained as drive(s) with longer wait queues holding back the others I guess?). Your data does strongly support my hypothesis that using a slice on 'sd0' would slow down writes. It may also be that your boot drive is a different type and vintage from the other drives. ZFS disables (or rather, doesn't enable) the drive's write cache when it's using a slice. It can be manually enabled, however. The swap slice on your first disk is what's limiting your performance. SATA drives are cheap this days so perhaps you can find a way to add a fourth drive which is at least as good as the drives you are using for c1t1d0 and c1t2d0. Using a separate boot volume with a swap slice on it might be a good idea. You'll be able to upgrade or reinstall your OS without touching the zpool. -B -- Brandon High [EMAIL PROTECTED] The good is the enemy of the best. - Nietzsche ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
Re: [zfs-discuss] ZFS raidz write performance:what to expect from SATA drives on ICH9R (AHCI)
On Thu, 17 Apr 2008, Tim wrote: Along those lines, I'd *strongly* suggest running Jeff's script to pin down whether one drive is the culprit: But that script only tests read speed and Pascal's read performance seems fine. Bob == Bob Friesenhahn [EMAIL PROTECTED], http://www.simplesystems.org/users/bfriesen/ GraphicsMagick Maintainer,http://www.GraphicsMagick.org/ ___ zfs-discuss mailing list zfs-discuss@opensolaris.org http://mail.opensolaris.org/mailman/listinfo/zfs-discuss
