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Hello Yall, |
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I'm starting to play with DRBD to build a small (2-node) failsafe cluster here. |
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The problem is, although DRBD starts really quickly with my SATA |
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drive, with the MD (software RAID) device it's REALLY slow. |
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It's like: |
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Dec 7 18:41:12 mail0 drbd0: resync bitmap: bits=87603792 words=2737620 |
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Dec 7 18:41:12 mail0 drbd0: size = 334 GB (350415168 KB) |
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Dec 7 18:44:49 mail0 drbd0: 0 KB marked out-of-sync by on disk bit-map. |
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Dec 7 18:44:50 mail0 drbd1: resync bitmap: bits=50975584 words=1592988 |
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Dec 7 18:44:50 mail0 drbd1: size = 194 GB (203902336 KB) |
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Dec 7 18:44:51 mail0 drbd1: 0 KB marked out-of-sync by on disk bit-map. |
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|
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DRBD0 is built over /dev/md4 that is built over two SATA disks. |
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While this load process is running, I tried a dstat -df to see what |
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disk activity I'm having and I found out that DRBD was reading at |
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100Kbps. |
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|
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On the other server it happens exactly otherwise. That's because the |
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DRBD0 is on the SATA and DRBD1 is on the MD4: |
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|
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Dec 7 18:41:12 www0 drbd0: resync bitmap: bits=87603792 words=2737620 |
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Dec 7 18:41:12 www0 drbd0: size = 334 GB (350415168 KB) |
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Dec 7 18:41:14 www0 drbd0: 0 KB marked out-of-sync by on disk bit-map. |
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Dec 7 18:41:14 www0 drbd1: resync bitmap: bits=50975584 words=1592988 |
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Dec 7 18:41:14 www0 drbd1: size = 194 GB (203902336 KB) |
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Dec 7 18:43:19 www0 drbd1: 0 KB marked out-of-sync by on disk bit-map. |
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And that proves that it is a problem with the DRBD-SoftwareRAID couple. |
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Versions: |
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Kernel: 2.6.18-gentoo-r3 |
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DRBD: 0.7.22 (although it's not on Portage, it's the only one that |
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works with kernel 2.6.18). |
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Thank you all. |
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|
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Best regards, |
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Daniel Colchete |
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-- |
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